Grounded Truth Map
Every claim, its certainty tier, source papers, and review status. The complete dataset — traceable to the original DOIs.
When multiple studies are synthesized into a claim, the combined evidence determines the certainty tier (High, Moderate, or Low) you see below. The tier is calculated algorithmically — not editorially.
Protein
9 claimsIs There a Limit to How Much Protein Your Body Can Use Per Meal?
The collective evidence from independent dose-response studies and isotope-tracer research shows no upper limit to how much protein the body can use from a single meal for muscle building —…
Do You Need More Protein After 40 to Keep Your Muscle?
After roughly age 40 the per-meal protein dose needed to fully activate muscle building rises by about 60 percent — from around 0.25 g/kg to 0.40 g/kg of body weight…
Plant vs Animal Protein for Muscle: What 2 Studies Found
The collective evidence from a 12-week controlled training study comparing habitual vegans and omnivores, reinforced by a meta-analysis of 9 independent trials totalling 266 participants, shows that plant protein produces…
How Much Protein When Losing Weight? (24-Study Answer)
The collective evidence from a 24-RCT meta-analysis covering 1,063 dieters shows that raising protein intake to roughly 1.2 g/kg of body weight per day during an energy-restricted diet consistently preserves…
Can You Actually Build Muscle While Losing Fat?
The collective evidence from a controlled feeding trial and an independent RCT in trained athletes shows that gaining muscle while losing fat in an energy deficit is physiologically possible when…
Do You Need Protein Within 30 Minutes of Training?
The collective evidence from a meta-analysis of 23 randomised controlled trials covering 525 participants shows that consuming protein within one hour of resistance exercise produces no significant advantage for muscle…
Does Spreading Protein Across Meals Build More Muscle?
The collective evidence from a crossover feeding study and an independent post-exercise dose-distribution trial shows that spreading the same total daily protein evenly across three to four meals produces approximately…
Does Excess Protein Turn Into Body Fat?
Two independent trials in resistance-trained men and women show that consuming 3.4 to 4.4 g/kg of protein per day — roughly three times the muscle-building ceiling and more than five…
How Much Protein Do You Actually Need Per Day to Build Muscle?
Across 49 randomised controlled trials covering 1,863 participants, adding protein to resistance training increased gains in fat-free mass, and those gains stopped rising at an estimated 1.62 g/kg of body…
Meal Timing
6 claimsIs Fasted Cardio Actually Better for Burning Fat?
Fasted cardio burns more fat during the workout itself, but every controlled study and meta-analysis measuring body composition over time finds identical fat loss between fasted and fed exercise —…
Does When You Eat Actually Matter? What 7 Controlled Studies Found
Every controlled experiment that isolated a meal-timing variable — eating window, meal frequency, breakfast, late-night eating, fasted exercise — found that body composition outcomes converged on total calorie and protein…
Is skipping breakfast really making you gain weight?
Skipping breakfast does not cause weight gain — two independent meta-analyses of controlled experiments found that breakfast skippers lost slightly more weight than breakfast eaters, though the effect was modest…
Does Eating Late at Night Actually Make You Gain Fat?
Eating late at night does not directly cause fat gain through a different metabolic pathway, but it triggers three converging biological shifts — doubled hunger, reduced energy expenditure, and fat-cell…
Does intermittent fasting actually give you a better body than regular dieting?
Intermittent fasting preserves muscle while losing fat as effectively as standard calorie restriction, with a possible but uncertain additional fat loss advantage in trained lifters eating adequate protein.
Does Eating More Often Actually Speed Up Your Metabolism?
Eating more frequently does not speed up metabolism — a meta-analysis of 16 randomized trials found no difference in weight, body fat, BMI, blood sugar, insulin, or any cholesterol marker…
Carbs
11 claimsHow Many Carbs Per Day to Lose Fat? What 5,192 Participants Revealed
There is no specific carb number that drives fat loss — at matched calories and adequate protein, swapping carbs for fat across 32 controlled feeding studies changed daily fat loss…
Is sugar — and fructose specifically — uniquely fattening compared to other carbs?
Sugar is not uniquely fattening at the same calories — when researchers swapped sugar for other carbohydrates in 12 controlled trials, body weight changed by 0.04 kg — but sugar…
Does Glycemic Index Matter for Fat Loss? 14 Trials, One Answer
Choosing low-GI carbs does not produce meaningful extra fat loss — fourteen pooled trials found a non-significant 0.62 kg weight difference over six or more months with zero heterogeneity, confirmed…
Does Fiber Accelerate Fat Loss? What 62 Pooled Trials Found
Viscous fiber supplementation produces a real, reproducible, but individually modest body-weight reduction without deliberate calorie restriction — consistent across sixty-two pooled trials covering 3,877 participants and confirmed by independent whole-food…
Do Carbs Trigger an Insulin-Driven Hunger Loop?
Carbs do not trigger an insulin-driven hunger loop — controlled ward studies show that high-carb diets produce less spontaneous eating and identical hunger compared to ketogenic diets, and a 2025…
How Many Carbs Per Day to Build Muscle?
Carbohydrate intake does not appear to independently drive muscle hypertrophy — eleven pooled RCTs with protein matched found no significant effect of higher carbs on muscle growth, at low certainty…
Do You Have to Cut Carbs to Lose Fat?
Cutting carbs is not required for fat loss — controlled trials consistently show that low-carb and balanced diets produce virtually identical body-fat outcomes when overall food quality and calorie intake…
Are Ultra-Processed Foods Making You Gain Weight?
Ultra-processed foods consistently drive excess calorie intake and weight gain even when matched nutrient-for-nutrient against whole foods — not through taste preference or metabolic disruption, but through physical properties that…
Does Carb Timing Actually Matter? What 4 Analyses Found
When daily carbohydrate and protein intake meet training demands, rearranging carbs around workouts — cycling, backloading, or rushing them post-session — produces no meaningful body-composition advantage in people who train…
Will Keto Wreck Your Strength? What 6 Trials Actually Found
Dropping carbs to cut does not wreck maximal strength — six pooled RCTs of trained lifters on keto for 8-12 weeks found no significant loss in squat or bench, with…
Does Cutting Carbs Burn More Calories? What 2 Studies Actually Found
Cutting carbs probably produces a real but modest increase in energy expenditure during dynamic weight states — likely 50 to 150 calories per day, not the 278 that viral clips…
Supplements
9 claimsDoes Creatine Build Real Muscle or Just Water Weight?
Creatine supplementation produces genuine increases in fat-free mass and functional strength that persist across age groups, sexes, and training backgrounds — though the earliest gains include some water pulled into…
Does Fish Oil Help Build Muscle?
Omega-3 fish oil supplementation has no measurable effect on muscle protein synthesis — a finding that held across every dose, duration, age group, and training condition researchers tested — while…
Which Supplements Actually Work for Building Muscle — and Which Are a Waste of Money?
Across eight independent meta-analyses and systematic reviews spanning more than 10,000 participants, only three supplement categories — creatine, protein (whey), and caffeine — produced reliable, replicated evidence of performance or…
Do Fat Burners Actually Work? 21 Studies, 2,359 People, One Answer
Across 21 studies and 2,359 participants, no fat burner supplement produced a reliable improvement in body composition — every confidence interval crossed zero — while diet and exercise alone proved…
Do I need protein powder or can I just eat chicken and eggs?
Across the largest head-to-head comparison of protein supplements ever conducted — 78 studies, nearly 5,000 people, 13 supplement types ranked simultaneously — only two types produced any measurable benefit over…
Are BCAAs Worth It If You Already Eat Enough Protein?
When dietary protein intake is adequate, BCAA supplements add nothing measurable for muscle growth — only one of five body composition studies found any benefit, the biochemistry shows three amino…
Do testosterone boosters build muscle?
Across a landscape of 50 commercial products, 109 ingredients, and four independent evidence reviews, testosterone booster supplements have almost no scientific foundation for their muscle-building claims — three out of…
Does Pre-Workout Actually Make You Stronger? What 4 Meta-Analyses Found
Caffeine produces a real, statistically significant improvement in maximal strength — confirmed at nearly identical effect sizes across independent meta-analyses spanning thousands of participants — but the boost sits on…
Does Collagen Actually Do Anything for Training, or Is It Just Broken-Down Protein?
Across 19 controlled studies and 768 people, collagen peptides combined with resistance training produced measurable gains in lean mass and strength — but through a completely different biological mechanism than…
Fat Loss
9 claimsHow do I lose belly fat specifically — can I target it?
No diet type, exercise modality, or targeted abdominal training preferentially removes belly fat — fat loss location is determined primarily by genetics and hormones, not by what you eat or…
Does It Matter What You Eat, or Just How Much, for Fat Loss?
The total amount you eat determines fat loss, not whether you cut carbs or follow a specific diet — the largest review ever conducted (61 trials, 6,925 people) found roughly…
Cardio vs. Weights for Fat Loss: Which Exercise Actually Changes Your Body?
Resistance training during a calorie deficit preserves substantially more muscle than cardio or dieting alone — a 62-study ranking placed all resistance modalities above all aerobic modalities for lean mass,…
Can protein change whether you lose fat or muscle during a cut?
When calories and fat are held constant, swapping carbohydrates for protein shifts the composition of weight loss — 24 randomized trials totaling 1,063 people found the higher-protein groups lost 0.87…
Do Diet Breaks Work — Can You Pause a Cut Without Losing Progress?
Planned diet breaks at maintenance calories produce the same fat loss, weight loss, and body measurements as continuous dieting — across 12 randomized trials and 881 people, the two approaches…
Is Starvation Mode Real — Will Dieting Slow Your Metabolism?
Metabolic adaptation after weight loss is real — 27 of 33 studies confirmed it — but the actual cost is 30 to 100 calories per day in people following normal…
How Do I Protect My Muscle Mass on Ozempic or Other GLP-1 Medications?
Across 86 controlled trials totaling over 5,400 participants, two behavioral strategies — higher protein intake and resistance training — consistently preserved lean mass during calorie deficits created by any means,…
How Fast Can I Realistically Lose Fat?
For people who lift, a deficit of about 500 calories per day is where lean-mass gains from training were predicted to stop and lean mass to hold; deeper deficits predicted…
Do I Have to Count Calories to Lose Weight — or Is There Another Way?
Calorie counting adds a measurable 3.3 kilograms of extra weight loss over 12 months — but programmes that never asked anyone to track still produced weight loss, and the psychological…
Training
9 claimsDo You Need Heavy Weights to Build Muscle?
Across 21 controlled experiments, 192 additional articles in a network meta-analysis, and fiber-level biopsy data, muscle growth was statistically identical between light and heavy weights — provided every set was…
HIIT for Fat Loss: 29 Trials Measured the Afterburn at 5 Grams Per Day
Across 29 randomized trials and 807 participants, HIIT produced virtually the same fat loss as steady-state cardio — the statistically significant advantages in body fat percentage and waist circumference were…
The Best Exercise for Fat Loss Doesn’t Exist — Here’s What 65 Trials Actually Reveal
Three independent evidence streams — 65 randomized trials comparing exercise modes, 29 trials comparing exercise intensities, and a landmark energy expenditure study across five countries — converge on the same…
Cardio vs Weights for Fat Loss — 36 Trials, One Surprising Answer
Across 36 randomized trials and 1,564 people, the fat loss difference between cardio, weights, and doing both was approximately one kilogram — and when total work was equalized between groups,…
Will Lifting Weights Make You Bulky? 29 Studies Measured the Difference
Across 29 studies and 2,815 measurements, men and women built muscle at virtually the same relative rate — the difference was 0.69%, too small for the meta-analysis to determine which…
Does Cardio Kill Your Gains? What 43 Studies Found
In a meta-analysis of 43 studies and 1,090 participants, adding cardio to a strength training program did not compromise muscle growth or maximal strength; the one cost it found was…
How Many Sets Per Week Do You Need to Build Muscle?
Across 67 studies and 2,058 participants, more weekly sets produced more muscle growth with 100% probability — but the returns diminished sharply after roughly ten fractional sets per muscle, and…
The Exercise Advice Women Over 40 Keep Getting Is Solving the Wrong Problem
Across six independent evidence streams covering more than 5,200 participants, a woman over 40 builds muscle at the same percentage rate as a man, loses fat equally well with cardio,…
Why Isn’t All This Exercise Making Me Lose Weight?
Your body enforces a calorie ceiling — above moderate activity levels, additional exercise does not proportionally increase total daily energy burn, and the compensation grows more aggressive the more body…
Sleep & Recovery
10 claimsWill Working Out at Night Wreck Your Sleep?
The largest meta-analysis on evening exercise and sleep — 23 controlled experiments, 275 participants — found no negative effect on sleep onset, sleep duration, sleep efficiency, or subjective sleep quality,…
Why do you eat everything in sight when you’re tired?
Sleep deprivation increases daily food intake by approximately 385 calories with no compensatory increase in energy expenditure, driven primarily by heightened reward-system activity in the brain rather than changes in…
Does Sleep Affect Whether You Lose Fat or Muscle?
Inadequate sleep attacks fat loss through three independent, simultaneous mechanisms: it shifts the calorie deficit from burning fat to burning muscle, drives 300-400 extra daily calories through the brain's reward…
Why Are You Losing Weight but Not Looking Leaner?
When the same people ate the same calorie-restricted diet twice — once sleeping 8.5 hours, once sleeping 5.5 — both lost about three kilograms, but adequate sleep produced 56% fat…
Can one bad night of sleep cost you muscle?
The evidence points to sleep loss throttling the body's ability to build muscle from food at the cellular level: a single sleepless night cut postprandial muscle protein synthesis by 18%…
How Much Does a Bad Night Actually Hurt Your Workout?
A meta-analysis of 77 controlled studies found that acute sleep loss reduces exercise performance by a weighted mean of 7.56% across every category tested — but the damage is profoundly…
How Much Sleep Do You Actually Need to Build Muscle?
The evidence across five studies reveals that sleep loss attacks muscle building on three separate biological levels — cellular, hormonal, and functional — each verified independently by different research teams…
Does Sleep Deprivation Cause Belly Fat?
In the most controlled sleep-and-body-composition experiment ever published, two weeks of four-hour nights redirected fat storage toward the organs — an 11% increase in visceral fat that was invisible to…
Can You Fix Weekday Sleep Debt by Sleeping In on Weekends?
The evidence points to weekend catch-up sleep recovering roughly a tenth of a workweek's sleep debt while failing to prevent weight gain, insulin sensitivity decline, or circadian disruption — and…
Does Sleep Deprivation Lower Testosterone?
The evidence on sleep and testosterone tells two different stories depending on severity: one controlled lab study found that a week of five-hour nights dropped daytime testosterone by 10-15% in…
Mindset & Adherence
5 claimsWhat’s the Best Diet for Weight Loss?
When compared across 121 randomized trials and 21,942 participants, 14 popular named diets — including low-carb, low-fat, Mediterranean, Atkins, and paleo — produce nearly identical weight loss at 6 and…
How Do You Keep Weight Off After Losing It?
Across 49 studies and 31,741 participants, long-term weight maintenance is predicted by four behavioral factors — self-monitoring weight, increasing physical activity, reducing energy-dense foods, and managing emotional eating — while…
Does Tracking Your Food Help You Lose Weight?
Across 12 randomized controlled trials and 1,190 adults with overweight or obesity, digital food and exercise tracking produced 2.87 kg more weight loss than no tracking — an effect that…
Why Did My Weight Loss Stop?
Mathematical modeling validated against four clinical datasets demonstrates that the commonly observed six-month weight-loss plateau is generated by gradually declining dietary adherence — not metabolic adaptation, which changes how much…
Is Flexible Dieting Better for Your Physique Than Clean Eating?
Across one randomized trial and two large observational studies totaling over 56,000 participants, flexible and rigid dieting produce identical fat loss during caloric restriction, but rigid dietary control consistently predicts…
Dietary Fat
4 claimsDoes Eating Fat Make You Fat? What 57,000 People Show
Fat does not make you fat — calories do. Across 57,000+ participants in 37 randomized controlled trials, reducing dietary fat produced only modest weight loss (about 1.4 kg), and the…
How Many Grams of Fat Per Day? The Answer Has Three Parts
The evidence across three independent research angles — a Cochrane review of 57,079 participants showing fat amount does not determine weight change when calories are controlled, body composition data showing…
Does It Matter Which Type of Fat You Eat for How Your Body Looks?
The type of fat you eat during a calorie surplus affects your body composition: polyunsaturated fat produces significantly more lean tissue and less body fat than saturated fat at identical…
How much fat do you need to keep your testosterone normal?
Dropping dietary fat below roughly 20% of total calories — well below typical intake — probably produces a small testosterone decrease in men, based on six old crossover studies with…
Recovery
8 claimsBest Recovery Method After Working Out — Ranked by Evidence
Based on a 99-study meta-analysis, massage is the most effective recovery method for reducing post-workout soreness — roughly five times more effective than cold water immersion. Active recovery, compression garments,…
Can You Overtrain From Lifting Weights?
In 25 years of deliberate attempts across 22 controlled studies, researchers have never reliably produced overtraining syndrome through resistance exercise alone. What most lifters experience — performance dips that resolve…
Does Sauna Bathing Help With Recovery and Muscle Growth — or Is the Growth Hormone Hype a Myth?
Within the forty studies examined in this systematic review, not a single one measured whether sauna bathing builds muscle — and the proposed mechanism (growth hormone spikes driving hypertrophy) was…
Do Ice Baths Actually Hurt Your Muscle Growth — and When Should You Avoid Them?
Regular cold water immersion after resistance training probably blunts muscle growth — an 8-study meta-analysis gives it a 95.7% probability. CWI also impairs strength gains (SMD = -0.60) while leaving…
Ice Bath or Sauna — Which Is Better for Recovery After Training?
Cold water immersion measurably reduces post-workout soreness and fatigue but carries a 95.7% probability of blunting muscle growth over time — while sauna has never been tested for recovery or…
Do Compression Garments Actually Help with Recovery — or Is It Placebo?
Compression garments produce statistically significant effects on soreness, power, and muscle damage recovery — but every effect size barely clears the threshold for 'moderate,' zero studies have solved the placebo…
What Does Foam Rolling Actually Do for Recovery?
Foam rolling reduces perceived muscle soreness after exercise — a real effect experienced by roughly two out of three people — but the evidence does not show it significantly speeds…
Does Taking Ibuprofen After Training Actually Hurt Your Muscle Growth?
Standard-dose daily ibuprofen roughly halves muscle growth in young, untrained adults during resistance training, but the effect appears to reverse in experienced lifters — making the answer depend on training…
Calories & Metabolism
8 claimsWhen Does Your Metabolism Actually Start Slowing Down?
Total and basal metabolic rate, adjusted for body composition, remain stable from age 20 to approximately 60 — with the first measurable decline beginning around age 63 at roughly 0.7%…
Why Do You Eat Way More Than You Think — Even When You Track Everything?
Every dietary tracking method ever tested against gold-standard measurement underestimates real calorie intake by 11–47%. In a landmark Columbia University study, subjects who believed they ate 1,028 kcal/day were actually…
Can You Trust the Calories Your Apple Watch Says You Burned?
Wearable fitness trackers overestimate calorie expenditure by approximately 28% on average — nearly three times the accepted 10% accuracy threshold — with no device brand, model, activity type, or user…
How Accurate Is Your Calorie Calculator — And Which Equation Should You Trust?
The Mifflin-St Jeor equation is the most accurate widely available calorie calculator equation — predicting resting metabolism within 10% for 82% of non-obese adults and 70% of obese adults. But…
Is the Obesity Crisis Caused by Sitting Too Much — or Eating Too Much?
The modern obesity epidemic is driven by increased energy intake, not decreased physical activity — doubly labeled water measurements across two decades show physical activity expenditure slightly increased while obesity…
Does Crash Dieting Permanently Damage Your Metabolism?
Extreme crash dieting creates persistent metabolic suppression that worsens over time — measured at 499 fewer calories burned per day six years after massive weight loss, with the people who…
Why can your friend eat more than you and stay lean — and what is actually going on?
The strongest evidence on why some people resist fat gain when they eat the same surplus points to non-exercise activity thermogenesis (NEAT), the energy of everyday movement outside exercise: in…
Protein’s Thermic Edge Over Carbs and Fat — The Fine Print
Protein generates significantly more diet-induced thermogenesis than other macronutrients at every meal — an acute effect confirmed across 52 controlled studies that is largest in lean, younger bodies but does…
Micronutrients & Minerals
6 claimsDo Multivitamins Actually Do Anything for Your Body?
Across 19 meta-analyses covering 5.5 million participants, multivitamin supplementation shows zero benefit for mortality, cardiovascular health, cancer prevention, infection risk, or exercise performance in healthy adults — and the only…
Is Low Iron Killing Your Training?
Undiagnosed iron deficiency costs female athletes up to 19% of their endurance — and the effective supplementation dose is five times what most multivitamins deliver.
Does Zinc Boost Testosterone — and Is ZMA Worth It?
Zinc deficiency reliably reduces testosterone and correcting it restores hormonal baseline, but supplementing beyond adequate levels — including ZMA — shows no testosterone or body-composition benefit, with the sole positive…
Does Vitamin D Make You Stronger?
Vitamin D supplementation reliably raises blood levels in athletes but does not significantly improve overall muscle strength — the one exception is quadriceps contraction, a preliminary result from two studies…
How Much Does Magnesium Really Help Your Sleep?
Oral magnesium supplementation reduced sleep onset latency by 17 minutes in three small trials of older adults with insomnia, but total sleep time did not significantly improve, evidence quality is…
Can Magnesium Reduce Muscle Soreness After Training?
Four studies with 73 total participants unanimously found that magnesium supplementation reduced muscle soreness or protected against exercise-induced muscle damage — a 100% positive hit rate from a systematic review…
Aging & Muscle Preservation
7 claimsHow Much Protein Do You Need During Weight Loss After 50 to Keep Your Muscle?
Older adults who eat at least 1.0 g of protein per kilogram of body weight each day preserve significantly more muscle during calorie-restricted weight loss — about 0.83 kg more…
Do Declining Hormones After 40 Actually Stop You From Building Muscle?
The age-related decline in testosterone and other anabolic hormones does not meaningfully limit muscle-building capacity from resistance training, as long as hormone levels remain within the clinically normal range —…
How Much Training Do You Actually Need to Build Muscle After 60?
Adults over 60 build more muscle and gain more functional mobility from low-volume resistance training — about 12 lower-body sets per week across two sessions — than from programs with…
Is Creatine Worth Taking After 60?
Creatine supplementation combined with exercise significantly strengthens older adults — adding approximately 2.1 kg to maximum strength (P=0.001, I²=0%) across 20 randomized controlled trials with 1,093 participants who are 69%…
Can Exercise Reverse the Body Composition Changes From Menopause?
Resistance training and combined exercise programs reverse postmenopausal body composition shifts — building muscle and reducing body fat percentage — with identical effectiveness whether a woman is 55 or 75,…
What type of strength training actually prevents age-related muscle loss?
In older adults with diagnosed sarcopenia, resistance training significantly improves strength and physical function, mostly by less than clinically meaningful amounts, while pooled muscle mass does not rise significantly except…
Do You Lose All Your Muscle Gains If You Stop Training — and How Fast Do They Come Back?
Taking three months off from training after 60 costs less than most people fear — and the comeback is faster than the original build. In Blocquiaux's 30 older men (58-77),…
Women’s Fitness & Hormones
5 claimsIs the Birth Control Pill Sabotaging Your Muscle Growth?
Oral contraceptive pill use has no meaningful effect on muscle hypertrophy, strength gains, or exercise performance — the combined evidence from 325 women across 8 studies shows an effect size…
Does Your Menstrual Cycle Affect Your Workout?
The largest analysis ever conducted on menstrual cycle phase and exercise performance — 78 studies covering 1,193 women — found the effect is trivially small and disappears entirely in well-designed…
Am I Losing Muscle Because of Menopause — And Can Lifting Fix It?
Lean mass declines measurably during the menopausal transition — approximately 2.5% by perimenopause and 5.7% by postmenopause — with the fastest losses concentrated during the transition years. But the evidence…
When Does Menopause Change Your Body Composition — And Does It Ever Stop?
Body composition changes significantly during the menopause transition — fat gain nearly doubles while lean mass reverses from gain to loss — but these changes are concentrated in a roughly…
What actually changes about fitness after 40 for women?
Body composition changes substantially after 40 for women — but the evidence tells a story that contradicts conventional wisdom on three counts. First, the changes are real but bounded: fat…
Food Science & Bioavailability
7 claimsHow Much Fat Do You Need to Absorb Nutrients From Vegetables?
About two teaspoons of unsaturated oil is enough to take carotenoid absorption from vegetables from near zero to its practical ceiling — and unsaturated fats outperform saturated fats by roughly…
What Foods Help Your Body Absorb More Iron?
Vitamin C, meat, fish, and fermented soy products each independently increase non-heme iron absorption through different mechanisms — and their effects are dose-dependent, additive, and strong enough to shift the…
Do Anti-Nutrients in Beans and Grains Block Mineral Absorption?
Phytic acid in beans and grains reduces iron and zinc absorption in the majority of controlled human feeding studies — and the same body of evidence shows that traditional kitchen…
Does Cooking Vegetables Destroy Their Nutrients?
Cooking increases the total antioxidant power of vegetables in 26 of 27 controlled measurements — but the word 'nutrients' covers dozens of compounds that each respond differently to heat, and…
Are Frozen Vegetables as Nutritious as Fresh?
Two separate laboratory analyses of eight fruits and vegetables find frozen produce retains comparable or higher levels of most nutrients — with vitamin E more than doubling in frozen peas…
Does Cooling and Reheating Rice Reduce Calories?
Cooling rice increases its resistant starch content by roughly 1.6 times, but the calorie reduction per serving — about 20 calories — falls far short of the viral '50% fewer…
Does turmeric with black pepper really boost absorption by 2000%?
The 2000% absorption figure originates from a single 1998 study of 8 men where curcumin without piperine was near the detection limit of the equipment, making the percentage an artifact…
Exercise Selection
6 claimsDoes Exercise Order Affect Muscle Growth?
Exercise order has no measurable effect on muscle growth — across 11 studies and 268 participants, the combined hypertrophy difference was 0.03 on a standardized scale with zero disagreement between…
Do You Need Isolation Exercises If You Already Do Compound Movements?
Compound exercises alone produce practically identical whole-muscle growth to programs that include isolation work — but that equivalence hides a critical detail. Within equal total growth, isolation exercises target specific…
Do Machines Build as Much Muscle as Free Weights?
Machines and free weights built similar amounts of muscle in the studies that measured it — no significant difference was found, though only five short studies did.
Does It Matter Which Exercise You Pick for Muscle Growth?
Exercise selection can change where muscle grows within a given muscle — different exercises can produce different regional hypertrophy patterns, and for the quadriceps, one exercise may not be enough…
Are Partial Reps as Effective as Full Range of Motion for Muscle Growth?
Overall, partial reps and full range of motion produce practically identical muscle growth — but not all partial reps are equal. Lengthened partials, performed in the stretched position, match or…
Does the Mind-Muscle Connection Actually Build More Muscle?
The mind-muscle connection — consciously focusing on squeezing the target muscle during each rep — nearly doubled bicep growth in one well-designed study of untrained men. But two studies examined…
Cardio & Conditioning
4 claimsCan you actually improve your cardio fitness after 40, 50, or 60?
Two independent meta-analyses covering 74 randomized trials in over 4,400 adults aged 60 and older consistently show that structured exercise meaningfully improves cardiovascular fitness — and it does not matter…
How Many Steps Per Day Do You Actually Need?
For most adults, the health payoff from daily steps largely levels off between 5,000 and 7,000 — well short of the popular 10,000 target — though the pattern flips for…
Is Zone 2 Cardio Actually Worth the Hype — Or Should You Just Go Harder?
For adults over 60, Zone 2 cardio and higher-intensity exercise produce statistically indistinguishable fitness improvements — the meta-analysis difference is 0.2 METs, not significant — though high-intensity exercise produces more…
How Much Cardio Do You Need Per Week?
Evidence from over 200,000 participants across four analyses — spanning daily step-count data and randomized exercise trials — consistently shows that the effective cardio dose plateaus well below standard guidelines,…
Alcohol & Body Composition
6 claimsDoes Alcohol Stop Fat Burning? What the Lab Data Shows
Alcohol cut fat burning sharply in two small lab studies: by 87% an hour into an intravenous dose, and by 73% one to two hours after two drinks. Neither followed…
How Many Drinks Per Week Is Too Many for Your Body Composition?
There is no single safe number of drinks per week for body composition. Four independent body systems — fat burning, muscle protein synthesis, sleep architecture, and body weight — each…
Does alcohol actually ruin your sleep — even one drink?
Based on 27 pooled studies (529 participants), alcohol disrupts REM sleep architecture at a dose-dependent rate — significant REM onset delay begins at approximately two standard drinks (0.35 g/kg), and…
Can You Drink Alcohol and Still Lose Weight and Build Muscle?
The evidence across three independent body systems — muscle protein synthesis (8 subjects, crossover), body weight (127 studies, 1.6 million people), and fat metabolism (22 subjects, isotope tracing) — converges…
How Much Muscle Growth Does Alcohol Actually Cost You?
Binge-level alcohol consumption (roughly 12 standard drinks) after exercise reduced muscle protein synthesis by 24-37%, depending on whether protein was co-ingested. Even optimal protein intake rescued only about a third…
Does Moderate Drinking Make You Gain Weight?
In a review of 127 observational studies and 1.6 million people, moderate drinking (14 to 28 g of alcohol a day) showed no significant link with being overweight, overweight or…
Satiety & Appetite Science
7 claimsCan You Eat More Food and Consume Fewer Calories?
Reducing the energy density of meals reliably cuts calorie intake — by an average of 709 calories per day when applied across all foods served — while the volume of…
Why Does Dieting Make You Hungrier — and Does It Ever Stop?
Weight loss triggers coordinated changes in at least eight appetite-regulating hormones that persist for at least one year — and for some satiety signals, the hormonal hunger drive actually worsens…
Does Your Body Force You to Overeat When Protein Is Too Low?
Below roughly 20% of calories from protein, the body systematically drives total energy intake upward — a pattern confirmed across 38 controlled dietary trials, over 9,000 free-living adults, and multiple…
Does HOW You Eat Matter as Much as WHAT You Eat?
Eating speed independently predicts calorie intake — confirmed by a 22-study meta-analysis and a 2,733-meal model where it operates alongside energy density and food palatability — but its effect is…
Why Do You Always Have Room for Dessert — Even When You’re Full?
Hyper-palatable food drives approximately 85 extra calories per meal through a reward-based hunger system that operates independently of physical fullness — which is why you always have room for dessert…
Which Fiber Types Actually Reduce Appetite — and Which Are a Waste of Money?
Of 38 commercially available fiber types studied across 107 treatments, only beta-glucan (from oats and barley), lupin kernel fiber, rye bran, whole grain rye, and mixed high-fiber meals consistently reduced…
Can Certain Foods Boost Your GLP-1 Naturally?
Protein at 35 grams or more per meal and specific fiber types — particularly beta-glucan from oats — acutely stimulate GLP-1 (the appetite hormone Ozempic targets), but the boost is…
Plant-Based Fitness
5 claimsHow Much Protein Do You Need on a Plant-Based Diet to Build Muscle?
At a matched 1.6 g/kg a day, vegans using soy protein built as much muscle as omnivores using whey over 12 weeks, and 17 trials found soy protein matched milk…
Is It Harder to Build Muscle on a Plant-Based Diet After 40?
Two meta-analyses covering 55 studies and 1,859 participants show that plant protein produces statistically indistinguishable muscle mass gains from animal protein in adults over 40 and over 60 (Reid-McCann: SMD=-0.05,…
Can Plant Protein Match Whey for Muscle Growth with Leucine or Blending?
A plant protein blend formulated to interlock amino acid profiles — wheat, corn, and pea in a 2:1:1 ratio — matched milk protein for muscle protein synthesis in a double-blind…
Does Soy Lower Testosterone in Men?
In healthy adult men, soy did not lower testosterone at any dose the randomized trials tested, and the separate body of muscle and strength research using soy in place of…
Is Creatine More Effective for Vegetarians and Vegans?
The evidence indicates that vegetarians and vegans experience substantially greater creatine store replenishment from supplementation than omnivores — driven by lower baseline levels that allow a super-compensation response — with…
Hydration & Electrolytes
5 claimsShould You Drink Water on a Schedule or When Thirsty?
During workouts up to about two hours, the evidence suggests thirst is a reliable drinking guide — athletes who followed their thirst consumed half as much fluid and performed equally…
Does Dehydration Make You Weaker in the Gym?
Dehydration shaves reps off your sets but barely touches your max — muscle endurance drops roughly 8%, strength about 5%, and explosive power stays flat, with no evidence that losing…
Does Swapping Soda for Water Actually Help You Lose Weight?
Pooled trial evidence finds that the effect of water interventions on body weight in overweight adults is indistinguishable from zero, but the type of beverage replaced is a significant moderator:…
Is a Gallon of Water a Day Better Than Drinking to Thirst?
Isotope-tracked water turnover across 5,604 people in 26 countries ranges roughly tenfold — from about one litre to ten litres per day — with body composition, physical activity, and climate…
Do You Need Electrolytes for a Normal Gym Workout?
Thirty-eight studies tested pre-exercise fluid loading with electrolytes across 403 participants and found conditional endurance benefits in prolonged exercise in heat — but every study tested athletes exercising for 60…
Chrononutrition & Shift Work
3 claimsWhy do shift workers eat 100-300 extra calories every day — and is it the schedule or the snacks?
Shift workers’ overconsumption is driven not by the calorie excess itself — which averages just 63 calories per day, roughly one cookie — but by a wholesale collapse in eating…
Does Working Night Shifts Actually Change Your Body Composition?
Across nearly 700,000 workers, shift work is associated with a real but modest body composition change — higher BMI and increased body fat — with the effect concentrated among men,…
Does Intermittent Fasting Work for Night Shift Workers?
In the largest and longest weight-loss trial in this population, night shift workers who fasted two days a week lost about as much weight as those who cut calories every…
Coaching, Structure & Support
5 claimsGroup or One-to-One Weight Loss Programme: Which Works Better?
In two reviews of weight-loss programmes that share no trial, adults in groups had lost more weight at a year than adults given one-to-one support: 1.9 kg more across seven…
Do Meal Plans Work for Weight Loss?
Across the studies we examined, having the food provided, as free prepackaged breakfasts and dinners with a written plan in one trial, or following a programme that included meal replacements,…
What Does a Human Coach Add to a Weight-Loss App?
Adding a human coach to a weight-loss app has not been shown to add weight loss over the same kind of app alone: in the five trials that compared the…
Is a Personal Trainer Worth It?
Across the trials we examined, a personal trainer's clearest repeated edge in trained lifters was a bigger squat. Pooled across six trials, supervision made almost no difference to body composition,…
Does Paying People to Lose Weight Work?
Paying people to lose weight helped in some designs and not in another, among the trials we examined: weekly cash of up to $25 for progress, on top of a…
Access this data
This dataset is available programmatically for researchers, LLMs, and integrations.
/wp-json/fitchef/v1/claims
All claims with filters for status, certainty tier, and topic.
ClaimReview + ItemList
Embedded in this page. Google Fact Check compatible.
Every claim passes through 5 verification gates across 3 pipelines. Studies pass three verification gates before publication. Claims are synthesized from multiple studies and reviewed for honest synthesis. Library items are checked for accurate representation. Claims are re-reviewed when new evidence is published.