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 Do You Actually Need Per Day to Build Muscle?
The collective evidence from 49 randomised controlled trials covering 1,863 participants converges on a daily protein ceiling of approximately 1.6 g/kg of body weight for maximising muscle growth during resistance…
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…
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…
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…
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…
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 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 independently drive muscle hypertrophy — eleven pooled RCTs found no significant effect of higher carbs on muscle growth when protein and total energy were sufficient, with…
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…
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,…
How Fast Can I Realistically Lose Fat?
A calorie deficit up to about 500 calories per day preserves the protective effect of resistance training on lean mass — but deficits beyond that threshold progressively strip muscle regardless…
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,…
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…
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…
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,…
Does Cardio Kill Your Gains? What 43 Studies Found
Across 43 studies and 1,090 participants, adding cardio to a strength training program produced zero meaningful interference with muscle growth or maximal strength — the only casualty was explosive power,…
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…
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 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…
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…
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All claims with filters for status, certainty tier, and topic.
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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.