86 studies

Nutrition

Nutritionwell supported · human dataAdded 21 August 2026
Intermittent fasting loses no more weight than plain dieting
Pooled results from 11 randomised trials lasting 8 to 24 weeks found intermittent energy restriction, including 5:2 regimens, produced essentially the same weight loss as continuous everyday dieting, with only a slight extra drop in fasting insulin of uncertain clinical relevance.
What it shows: A trustworthy null: results pooled from 11 trials where people were assigned at random to fasting-style or standard calorie cutting, and weight loss came out the same. All the trials ran 24 weeks or less, so longer-term differences remain untested.Meta-analysis · J Transl Med
Full breakdown →Energy balance explained Calorie Deficit Calculator Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: a systematic review and meta-analysis of randomized controlled trials. J Transl Med 2018
Nutritionpreliminary · human dataAdded 20 August 2026
Intermittent fasting looks muscle-safe in early trials
A systematic review of 10 studies in people under 60 found intermittent fasting may reduce fat mass while at least maintaining muscle in resistance-trained and overweight individuals, alongside improvements in glucose and insulin levels.
What it shows: Promising but thin: a sweep of all the studies on this found only 10, most of them small and all in people under 60, and the authors say the body composition picture is not yet settled. It also cannot say whether fasting beats ordinary dieting.Systematic review · Int J Food Sci Nutr
Full breakdown →Energy balance explained Calorie Deficit Calculator Effectiveness of intermittent fasting to potentiate weight loss or muscle gains in humans younger than 60 years old: a systematic review. Int J Food Sci Nutr 2021
Nutritionpreliminary · human dataAdded 20 August 2026
Plant protein holds its own against animal protein for muscle after 50
Across 29 randomised trials in 2,363 adults aged 50 and over, plant and animal protein produced similar effects on lean mass, handgrip strength and most blood markers; the one marginal difference favoured plant protein for total cholesterol.
What it shows: Reasonably solid: results pooled from 29 trials in 2,363 adults aged 50 and over, and the two protein sources performed alike on almost everything measured. The catch is that most trials tested soy powder against dairy powder, so swapping whole foods like beans for beef was barely studied.Study · Clin Nutr ESPEN
Full breakdown →Essential amino acids explained Protein Intake Calculator Plant- versus animal-derived protein and nutritional, cardiometabolic, and inflammatory outcomes in middle-aged and older adults: A systematic review and meta-analysis of randomized controlled trials. Clin Nutr ESPEN 2026
Nutritionpreliminary · human dataAdded 20 August 2026
Coffee drinkers carried less visceral fat at the same BMI
Among 2,264 Finnish adults assessed at age 46, higher habitual coffee intake was associated with lower total and visceral fat and higher skeletal muscle mass despite similar BMI across groups. In men, each extra cup a day was linked to higher total testosterone and SHBG but lower free testosterone; women showed only the SHBG and free testosterone pattern.
What it shows: Interesting but not proof: researchers measured 2,264 people at a single point in time, so coffee drinkers may simply differ in ways the analysis could not fully account for, even after adjusting for BMI, smoking, activity, education and alcohol. Nothing here shows coffee changed anyone's body or hormones.Study · Eur J Nutr
Full breakdown →Visceral fat explained Body Fat Calculator Associations of habitual coffee intake with testosterone and cardiometabolic markers: the Northern Finland birth cohort 1966 study. Eur J Nutr 2026
Nutritionwell supported · human dataAdded 20 August 2026
Exercise did not keep lost weight off, but meal replacements did
After rapid weight loss on very-low-calorie diets, meal replacements helped people keep off 3.9 kg more and anti-obesity drugs 3.5 kg more than controls in pooled trials, while high-protein diets preserved 1.5 kg more. Exercise programmes and dietary supplements showed no significant benefit for keeping the weight off.
What it shows: Strong for what it covers: results pooled from 20 trials with 3,017 people who first lost around 12.3 kg on very-low-calorie diets. The exercise evidence came from only five arms, so a benefit cannot be ruled out, but none was shown here.Meta-analysis · Am J Clin Nutr
Full breakdown →Metabolic adaptation explained Calorie Deficit Calculator Effects of anti-obesity drugs, diet, and exercise on weight-loss maintenance after a very-low-calorie diet or low-calorie diet: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr 2014
Nutritionwell supported · human dataAdded 20 August 2026
Fibre supplements did nothing for mood in the trials that tested them
Pooling 23 observational studies covering 181 405 people, higher fibre intake was associated with slightly lower depressive and anxiety scores, but 10 randomised trials of fibre supplements in 740 people found no benefit over placebo for either outcome.
What it shows: Strong evidence that the supplement version does not deliver: results pooled from 23 studies that followed 181 405 people plus 10 trials in 740 people. Only one of those trials included people with diagnosed depression, so fibre pills remain untested where they might matter most.Meta-analysis · Nutr Rev
Full breakdown →Executive function explained Fiber intake and fiber intervention in depression and anxiety: a systematic review and meta-analysis of observational studies and randomized controlled trials. Nutr Rev 2024
Nutritionwell supported · human dataAdded 20 August 2026
Intermittent fasting beat no diet at all, and matched every other one
Pooling nine randomised trials in 540 people with obesity, intermittent fasting produced no greater reduction in body weight or BMI than conventional control diets at any time point, and no difference emerged between alternate day fasting and time restricted eating.
What it shows: Reasonably solid on the headline point: results pooled from nine trials lasting longer than two months in 540 people with a BMI above 30, though the authors rated the quality of evidence low to moderate. Data on mood and well-being were too thin to pool at all.Meta-analysis · Nutr Metab Cardiovasc Dis
Full breakdown →Energy balance explained Calorie Deficit Calculator Effectiveness of intermittent fasting for weight loss in individuals with obesity: A meta-analysis of randomized controlled trials. Nutr Metab Cardiovasc Dis 2023
Nutritionwell supported · human dataAdded 19 August 2026
Intermittent fasting trims weight and blood fats, but not blood pressure
A meta-analysis of nine randomised trials in 899 Chinese adults found intermittent fasting reduced body weight, body fat, insulin resistance, LDL cholesterol and triglycerides compared with control groups, while waist circumference, fasting glucose and blood pressure did not change significantly.
What it shows: Reasonably solid for the short term: results pooled from nine trials in 899 Chinese adults agree on weight and body fat, but the trials were brief and mostly tested time-restricted eating, so long-term effects and other fasting styles remain open questions.Meta-analysis · Nutrients
Full breakdown →Energy balance explained Calorie Deficit Calculator Effect of Intermittent Fasting on Cardiometabolic Health in the Chinese Population: A Meta-Analysis of Randomized Controlled Trials. Nutrients 2024
Nutritionwell supported · human dataAdded 19 August 2026
Protein before your workout may switch on more muscle growth than after
Pooled trials show whey protein combined with exercise raises muscle protein synthesis in healthy adults, with a dose-dependent effect across 10 to 60 g and rises of up to 2.5-fold when 20-40 g is taken 45 minutes before multiple-set resistance exercise.
What it shows: Solid enough to take seriously: results pooled from 21 trials in healthy adults, with muscle building measured directly in biopsy samples. A bigger synthesis response over a few hours is not the same as more muscle after months of training, so the long-term payoff is still unproven.Meta-analysis · Nutrients
Full breakdown →Muscle protein synthesis explained Protein Intake Calculator Whey Protein Supplementation Combined with Exercise on Muscle Protein Synthesis and the AKT/mTOR Pathway in Healthy Adults: A Systematic Review and Meta-Analysis. Nutrients 2025
Nutritionwell supported · human dataAdded 19 August 2026
Protein powder without the lifting does nothing for ageing muscle
Extra protein on its own did not significantly improve lean mass or strength in adults over 50, in a pooled analysis of 28 randomised trials. Only when paired with resistance exercise did higher protein intake add limb lean mass and handgrip strength, with the clearest lean mass gains in sarcopenic or frail groups.
What it shows: Strong evidence with a clear split: results pooled from 28 trials in adults aged 50 and over show protein only pays off alongside lifting. The trials disagreed with each other considerably and most carried some risk of bias, so the true size of the benefit is uncertain.Meta-analysis · Am J Clin Nutr
Full breakdown →Muscle protein synthesis explained Protein Intake Calculator Protein interventions augment the effect of resistance exercise on appendicular lean mass and handgrip strength in older adults: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr 2022
Nutritionwell supported · human dataAdded 19 August 2026
Intermittent fasting shifts weight but leaves sleep untouched
Across 18 randomised trials in adults with overweight or obesity, intermittent fasting reduced weight, BMI, fat mass, waist circumference, daily energy intake and diastolic blood pressure compared with unrestricted eating, yet it did not improve sleep quality.
What it shows: Solid on the weight and blood pressure findings: results pooled from 18 trials comparing fasting schedules with unrestricted eating in adults with overweight or obesity. Sleep was only a secondary measure in most of the studies, so trials built to test sleep directly are still needed.Meta-analysis · Sleep Med Rev
Full breakdown →Energy balance explained Calorie Deficit Calculator The effects of intermittent fasting on sleep quality and cardiometabolic health outcomes in adults with overweight/obesity status: a systematic review and meta-analysis of randomized controlled trials. Sleep Med Rev 2025
Nutritionpreliminary · human dataAdded 18 August 2026
Intermittent fasting cuts weight but may raise LDL and cost lean mass
A pooled analysis of 28 randomised trials in 1833 adults found intermittent fasting reliably reduced body weight and BMI at every age, but fat-free mass fell in younger and older adults and LDL cholesterol rose. The authors rate the certainty of evidence low to very low and call the age-specific patterns hypothesis-generating.
What it shows: Treat this as a set of leads rather than verdicts: results pooled from 28 trials covering 1833 adults, yet the authors themselves rate the certainty low to very low. The age-by-age patterns, including the LDL rise, are flagged as hypothesis-generating and need larger trials.Meta-analysis · Nutrients
Full breakdown →Energy balance explained Calorie Deficit Calculator Age-Specific Analysis of the Effects of Intermittent Fasting on Body Composition and Cardiometabolic Markers in Healthy Adults and Individuals with Overweight or Obesity: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients 2026
Nutritionwell supported · human dataAdded 18 August 2026
Adding calorie counting to time-restricted eating buys you nothing extra
Time-restricted eating on its own cut body weight by 1.59 kg and fat mass by 0.93 kg versus no restriction across 20 randomised trials, but adding deliberate calorie restriction on top delivered no extra weight loss. Both approaches also trimmed around half a kilogram of fat-free mass.
What it shows: Solid pooled evidence: results pooled from 20 trials in 1242 adults all pointed the same way. The catch is the average extra loss was 1.59 kg, and some of it was fat-free mass rather than fat.Meta-analysis · Int J Behav Nutr Phys Act
Full breakdown →Energy balance explained Calorie Deficit Calculator Efficiency of time-restricted eating and energy restriction on anthropometrics and body composition in adults: a systematic review and meta-analysis of randomized controlled trials. Int J Behav Nutr Phys Act 2025
Nutritionwell supported · human dataAdded 18 August 2026
The weight lost on time-restricted eating was mostly lean mass, not fat
Pooled studies found time-restricted eating produced a 2.32% weight loss in overweight and obese adults, but the loss came mainly from lean mass rather than fat mass, and LDL cholesterol rose in the fasting groups.
What it shows: Worth taking seriously but not as settled: results pooled from randomised trials and some studies that did not assign people at random, in overweight and obese adults. The authors themselves urge caution for anyone with high cholesterol or already low muscle mass.Meta-analysis · Crit Rev Food Sci Nutr
Full breakdown →Sarcopenia explained Body Fat Calculator Missing puzzle pieces of time-restricted-eating (TRE) as a long-term weight-loss strategy in overweight and obese people? A systematic review and meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr 2023
Nutritionwell supported · human dataAdded 17 August 2026
Fasting 14 hours may match 16 for weight loss
Fasting for 14 hours a day may be as effective as 16 hours for weight loss, according to a sweep of 24 randomised trials of time-restricted feeding. The pattern produced moderate weight loss in people with overweight or obesity, and losses exceeded 5% of starting body weight when combined with calorie restriction.
What it shows: Encouraging but not settled: a sweep of 24 trials found consistent short-term benefits in people carrying extra weight, but the trials were mostly brief and the authors themselves call for longer, better designed studies.Systematic review · Nutrients
Full breakdown →Insulin sensitivity explained Calorie Deficit Calculator Effects of Time-Restricted Feeding and Ramadan Fasting on Body Weight, Body Composition, Glucose Responses, and Insulin Resistance: A Systematic Review of Randomized Controlled Trials. Nutrients 2022
Nutritionwell supported · human dataAdded 17 August 2026
Fasting is not magic: the calorie cut does the work
Across 167 trials with 11,998 adults, intermittent fasting patterns produced weight loss comparable to ordinary calorie restriction of the same size, and fasting regimens showed weight rebound after 12 weeks while continuous restriction did not. What mattered was the depth of the energy cut, not the meal timing.
What it shows: Strong evidence: results pooled from 167 trials in 11,998 adults with overweight, obesity or metabolic problems. Certainty ranged from low to high across the comparisons, and the rebound finding comes from a subgroup analysis, so it is the least firm piece.Meta-analysis · Nutr Rev
Full breakdown →Energy balance explained Calorie Deficit Calculator Comparison of Different Intermittent Fasting Patterns or Different Extents of Calorie Restriction for Weight Loss and Metabolic Improvement in Adults: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials. Nutr Rev 2026
Nutritionwell supported · human dataAdded 17 August 2026
Early eating windows burn fat and spare muscle
Eating earlier in the day under early time-restricted eating cut body weight by 1.84 kg, fat mass by 1.10 kg and visceral fat area by 9.76 cm2 versus unrestricted eating across 13 pooled trials, without a significant loss of fat-free mass. A 16:08 schedule, sixteen hours fasting to eight hours eating, looked best at preserving lean tissue.
What it shows: Fairly convincing on fat loss: results pooled from 13 trials in 859 people pointed the same way. The muscle-sparing conclusion is shakier, since the change in lean mass only just missed statistical significance and the trials were short.Meta-analysis · Diabetes Metab Syndr
Full breakdown →Visceral fat explained Body Fat Calculator Does early time-restricted eating reduce body weight and preserve fat-free mass in adults? A systematic review and meta-analysis of randomized controlled trials. Diabetes Metab Syndr 2024
Nutritionwell supported · human dataAdded 16 August 2026
Fasting beats plain calorie cutting by less than a kilogram of fat
Over six months or longer, intermittent fasting reduced body weight by 2.84 kg, fat mass by 3.06 kg and waist circumference by 3.85 cm versus a control diet in adults with overweight or obesity; against continuous calorie restriction its edge shrank to 0.70 kg more fat lost.
What it shows: Strong for a diet question: results pooled from 24 trials of 2032 adults with overweight or obesity, all lasting six months or more. The edge over ordinary calorie cutting was real but small, so neither approach clearly wins.Meta-analysis · Obes Rev
Full breakdown →Energy balance explained Calorie Deficit Calculator Longer-term effects of intermittent fasting on body composition and cardiometabolic health in adults with overweight and obesity: A systematic review and meta-analysis. Obes Rev 2025
Nutritionpreliminary · human dataAdded 16 August 2026
A daily juice did not crowd out whole fruit and veg
In a four-week trial of 42 adults who ate little fruit and veg, allowing one daily portion of juice or smoothie within UK 5-a-day advice did not significantly reduce whole fruit and vegetable intake: 6.6 portions a day versus 8.9 for whole produce alone, against 2.45 in the control group. The group including juice also reported lower depression symptoms than control, with no differences in anxiety, gut symptoms or metabolic markers.
What it shows: Suggestive but thin: one four-week trial in 42 healthy adults who were eating two servings a day or fewer, and every group was handed weekly cash for produce, so it tells you little about ordinary shopping. The mood result was a secondary outcome and the work was paid for by a fruit juice industry body, which is worth holding in mind.Study · Br J Nutr
Full breakdown →Including fruit juice and smoothies within 5-a-day fruit and vegetable intake recommendations: a randomised controlled trial investigating impact on levels of intake, mood and markers of health. Br J Nutr 2026
Nutritionwell supported · human dataAdded 15 August 2026
Plant protein matches animal protein for strength gains
A meta-analysis of 16 randomised trials found protein source, animal or plant, made no difference to gains in absolute lean mass or muscle strength. Animal protein showed a small edge on percent lean mass, and adults under 50 gained 0.41 kg more absolute lean mass with it.
What it shows: Reassuring for plant eaters: results pooled from 16 trials where protein intakes were already above recommended levels, so any advantage of source had room to show and mostly did not. The small animal protein edge appeared mainly in adults under 50, and doing resistance training alongside made no difference to the outcome.Meta-analysis · Nutrients
Full breakdown →Muscle protein synthesis explained Protein Intake Calculator Animal Protein versus Plant Protein in Supporting Lean Mass and Muscle Strength: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients 2021
Nutritionwell supported · human dataAdded 14 August 2026
Extra protein on a diet buys less than a kilo of extra fat loss
Pooled results from 24 calorie-matched trials in 1063 adults show higher-protein low-fat diets produced 0.79 kg more weight loss and 0.87 kg more fat loss than standard-protein versions, while better preserving fat-free mass and resting energy expenditure.
What it shows: About as solid as diet science gets: results pooled from 24 trials in 1063 adults, all prescribed the same calories and fat. The average diet ran only around 12 weeks, so whether the protein edge survives long term is unknown.Meta-analysis · Am J Clin Nutr
Full breakdown →Energy balance explained Protein Intake Calculator Effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: a meta-analysis of randomized controlled trials. Am J Clin Nutr 2012
Nutritionpreliminary · human dataAdded 14 August 2026
Fermented foods failed to move two of three inflammation markers
Pooled results from 26 randomised trials in 1461 adults found fermented foods lowered the inflammatory marker TNF-α but did not change CRP or IL-6.
What it shows: Take it lightly: results pooled from 26 trials in 1461 generally healthy adults, but the trials disagreed with each other so strongly that even the average TNF-α drop is hard to trust. The two most commonly cited inflammation markers did not move at all.Meta-analysis · Clin Nutr ESPEN
Full breakdown →Fermented foods explained Fermented foods and inflammation: A systematic review and meta-analysis of randomized controlled trials. Clin Nutr ESPEN 2020
Nutritionwell supported · human dataAdded 13 August 2026
Walnuts moved one blood fat and nothing else in metabolic syndrome
In a pooled analysis of 8 trials with 549 adults with metabolic syndrome, eating walnuts modestly lowered blood triglycerides but did not change cholesterol, blood sugar, insulin, inflammation, body weight, waist size or blood pressure.
What it shows: Solid as far as it goes: results pooled from 8 trials in 549 adults with metabolic syndrome, but the trials were few and fairly small. A modest triglyceride drop is the only effect that showed up reliably, so bigger benefits can be neither ruled in nor out yet.Meta-analysis · Pharmacol Res
Full breakdown →Metabolic syndrome explained Metabolic Fitness Index Impact of walnut consumption on cardio metabolic and anthropometric parameters in metabolic syndrome patients: GRADE-assessed systematic review and dose-response meta-analysis of data from randomized controlled trials. Pharmacol Res 2022
Nutritionwell supported · human dataAdded 13 August 2026
Meal replacements beat food-only diets by just over a kilo
Pooling 10 trials with 1254 people with pre-diabetes and features of metabolic syndrome, weight loss plans built around meal replacements beat conventional food-based diets by 1.38 kg of extra weight loss, with small added reductions in LDL cholesterol and systolic blood pressure.
What it shows: Believable but modest: results pooled from 10 trials in 1254 people with pre-diabetes, and the authors themselves rate the certainty of the evidence low to moderate because the trials were imprecise and sometimes disagreed with each other.Meta-analysis · Obes Rev
Full breakdown →Energy balance explained Calorie Deficit Calculator Weight management using meal replacements and cardiometabolic risk reduction in individuals with pre-diabetes and features of metabolic syndrome: A systematic review and meta-analysis of randomized controlled trials. Obes Rev 2024

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