Study analysis · Journal of Exercise and Nutrition · 2021
Is protein timing a myth? New study shows morning vs evening whey makes no difference for athletes.
Taking a daily whey protein shake helps athletes who don't eat enough protein reach their goals and feel fuller, no matter if they take it in the morning or at night.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study is like a test where athletes were given a protein drink in the morning or evening and asked how they felt. It shows that the drink helped them feel fuller and eat more protein, but it doesn't prove that it changed other things like sleep or stress, because there wasn't a fake drink to compare, and the study was small.
What’s the bottom line?
Athletes who don't eat enough protein were given a whey protein drink every day for two weeks, either in the morning or evening. The study found that taking the supplement helped them reach their protein goals and made them feel fuller, no matter when they took it.
How strong is this study?
The study was designed well because each athlete tried both morning and evening timing, which helps compare fairly. But it wasn't perfect: the athletes knew which drink they were getting, and only 29 people took part. So, the results are interesting but we need bigger, better studies to be sure.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
60 / 100
- Randomization+20/20
- Blindingnot blinded
- Control group+15/15
- Sample size (n=29)+2.7/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 560 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. Despite randomization, the lack of blinding, small sample size, use of self-reported outcomes, and short intervention periods limit the ability to establish causation confidently. Potential confounders (e.g., training load, diet variations) were not fully controlled.
No Conflicts
No conflicts of interest identified
No conflicts identified.
No funding or conflict of interest statements were found in the provided text. The study uses a commercial product (Dymatize ISO-100) but no industry affiliation is disclosed.
Key takeaways
- 01
Athletes increased protein intake from 1.1-1.3 g/kg to 1.5-1.7 g/kg.
- 02
Satiety scores rose from about 5.8 to 6.7-7.1 on a 11-point scale.
- 03
No changes in sleep, soreness, or fatigue.
- 04
The increase in fullness is noticeable and could help athletes avoid unhealthy snacking.
- 05
The lack of effect on other wellness measures suggests protein timing doesn't directly impact sleep or recovery in the short term.
Surprising findings
- When you take your whey protein shake (morning vs evening) doesn't change how much total protein you eat or how full you feel.Common advice stresses timing around workouts; this shows flexibility for daily supplementation.
- Seven out of 29 athletes remained protein-insufficient even with a daily supplement.One would assume a standard supplement dose solves deficiency, but individual needs vary.
Practical takeaways
If you're not meeting your protein needs, add one whey shake per day at any time that's convenient. It will boost intake and increase fullness.
This study was only 2 weeks, in athletes with low protein at baseline. No placebo control, so a placebo effect may be present.
medium confidenceDon't expect immediate improvements in sleep, soreness, or recovery from protein supplements alone. Focus on overall diet and training load.
Study duration was short; longer supplementation may show different results. Also, sleep and recovery are multifactorial.
high confidenceConsider individualizing protein supplement dosage; one scoop may not be enough for everyone. Seven athletes still fell short.
The supplement was dosed by weight range, not individually. More precise dosing may help.
medium confidenceWhy this study matters
Protein Timing Doesn't Matter for Total Intake
In 29 protein-insufficient collegiate athletes, supplementing with whey in the morning or evening both increased total protein intake from ~1.1-1.3 g/kg to ~1.5-1.7 g/kg, with no difference between timing (p=1.0).
It debunks the idea that you must time protein around workouts for general health and satiety benefits.
Whey Protein Boosts Satiety, Not Just Muscle
Satiety scores rose from 5.8 (washout) to 6.7-7.1 during supplementation on an 11-point scale (p<0.01). There was a positive correlation between protein intake and fullness (r=0.499, p<0.001).
Athletes often struggle with hunger during training; this suggests protein supplements can help control appetite.
No Effect on Sleep, Soreness, or Recovery
Despite popular claims, short-term whey supplementation did not significantly improve fatigue, sleep quality, soreness, stress, mood, or recovery in these athletes.
Many athletes take protein expecting better recovery, but this study shows no immediate perceptual benefit.
Higher Protein, Lower Stress?
There was an inverse correlation between protein intake and perceived stress (r=-0.321, p=0.019), suggesting more protein is linked to less stress.
Stress management is a huge topic; this finding opens a new angle for nutrition and mental health.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Athletes who don't eat enough protein were given a whey protein drink every day for two weeks, either in the morning or evening. The study found that taking the supplement helped them reach their protein goals and made them feel fuller, no matter when they took it.
Research results
Athletes increased protein intake from 1.1-1.3 g/kg to 1.5-1.7 g/kg. Satiety scores rose from about 5.8 to 6.7-7.1 on a 11-point scale. No changes in sleep, soreness, or fatigue.
What this means - more context
The increase in fullness is noticeable and could help athletes avoid unhealthy snacking. The lack of effect on other wellness measures suggests protein timing doesn't directly impact sleep or recovery in the short term.
To examine the effects of short-term whey protein supplementation timing (morning vs evening) on total protein intake and self-reported wellness measures in protein-insufficient collegiate athletes.
Short-term whey protein supplementation enabled protein-insufficient collegiate athletes to achieve recommended protein intake (≥1.5 g/kg BW) and increased satiety, with no differences between morning and evening timing. No significant effects were observed on fatigue, sleep quality, soreness, stress, mood, or recovery.
Methods Used
Randomized crossover trial with 29 protein-insufficient collegiate athletes (13 men, 16 women). Participants completed two 2-week supplementation periods (morning or evening whey protein) separated by a 2-week washout. Daily food logs and self-reported wellness measures were collected.
Main Finding
Protein supplementation increased absolute and relative protein intake to ~1.7 g/kg BW (men) and ~1.5 g/kg BW (women) vs baseline. Satiety was significantly higher during supplementation vs washout (men: p=0.004; women: p=0.012). No other wellness measures differed. Positive correlation between protein intake and satiety (r=0.499, p<0.001); inverse correlation with stress (r=-0.321, p=0.019).
Confidence Level
Moderate - small sample size (n=29), no placebo control, short duration (2 weeks per condition), but crossover design and consistent statistical findings.
Study Flags
Red Flags
- •No placebo control group
- •Short intervention duration (2 weeks per condition)
- •Small sample size (n=29)
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
When you take your whey protein shake (morning vs evening) doesn't change how much total protein you eat or how full you feel.
Common advice stresses timing around workouts; this shows flexibility for daily supplementation.
Practical Takeaways
If you're not meeting your protein needs, add one whey shake per day at any time that's convenient. It will boost intake and increase fullness.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 560 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study is like a test where athletes were given a protein drink in the morning or evening and asked how they felt. It shows that the drink helped them feel fuller and eat more protein, but it doesn't prove that it changed other things like sleep or stress, because there wasn't a fake drink to compare, and the study was small.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Randomized crossover design with washout period controls for individual variability.
- Use of DXA for body composition assessment.
- Clear inclusion criteria (protein-insufficient athletes).
Weaknesses
- No blinding (open-label), leading to potential performance and detection bias.
- Small sample size (n=29) limits statistical power and precision.
- No placebo supplement, so placebo effect cannot be assessed.
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Athletes who don't eat enough protein were given a whey protein drink every day for two weeks, either in the morning or evening. The study found that taking the supplement helped them reach their protein goals and made them feel fuller, no matter when they took it.
Research results
Athletes increased protein intake from 1.1-1.3 g/kg to 1.5-1.7 g/kg. Satiety scores rose from about 5.8 to 6.7-7.1 on a 11-point scale. No changes in sleep, soreness, or fatigue.
What this means - more context
The increase in fullness is noticeable and could help athletes avoid unhealthy snacking. The lack of effect on other wellness measures suggests protein timing doesn't directly impact sleep or recovery in the short term.
To examine the effects of short-term whey protein supplementation timing (morning vs evening) on total protein intake and self-reported wellness measures in protein-insufficient collegiate athletes.
Short-term whey protein supplementation enabled protein-insufficient collegiate athletes to achieve recommended protein intake (≥1.5 g/kg BW) and increased satiety, with no differences between morning and evening timing. No significant effects were observed on fatigue, sleep quality, soreness, stress, mood, or recovery.
Methods Used
Randomized crossover trial with 29 protein-insufficient collegiate athletes (13 men, 16 women). Participants completed two 2-week supplementation periods (morning or evening whey protein) separated by a 2-week washout. Daily food logs and self-reported wellness measures were collected.
Main Finding
Protein supplementation increased absolute and relative protein intake to ~1.7 g/kg BW (men) and ~1.5 g/kg BW (women) vs baseline. Satiety was significantly higher during supplementation vs washout (men: p=0.004; women: p=0.012). No other wellness measures differed. Positive correlation between protein intake and satiety (r=0.499, p<0.001); inverse correlation with stress (r=-0.321, p=0.019).
Confidence Level
Moderate - small sample size (n=29), no placebo control, short duration (2 weeks per condition), but crossover design and consistent statistical findings.
Study Flags
Red Flags
- •No placebo control group
- •Short intervention duration (2 weeks per condition)
- •Small sample size (n=29)
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
When you take your whey protein shake (morning vs evening) doesn't change how much total protein you eat or how full you feel.
Common advice stresses timing around workouts; this shows flexibility for daily supplementation.
Practical Takeaways
If you're not meeting your protein needs, add one whey shake per day at any time that's convenient. It will boost intake and increase fullness.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 560 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study is like a test where athletes were given a protein drink in the morning or evening and asked how they felt. It shows that the drink helped them feel fuller and eat more protein, but it doesn't prove that it changed other things like sleep or stress, because there wasn't a fake drink to compare, and the study was small.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Randomized crossover design with washout period controls for individual variability.
- Use of DXA for body composition assessment.
- Clear inclusion criteria (protein-insufficient athletes).
Weaknesses
- No blinding (open-label), leading to potential performance and detection bias.
- Small sample size (n=29) limits statistical power and precision.
- No placebo supplement, so placebo effect cannot be assessed.
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The study was designed well because each athlete tried both morning and evening timing, which helps compare fairly. But it wasn't perfect: the athletes knew which drink they were getting, and only 29 people took part. So, the results are interesting but we need bigger, better studies to be sure.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
60 / 100
- Randomization+20/20
- Blindingnot blinded
- Control group+15/15
- Sample size (n=29)+2.7/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 560 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. Despite randomization, the lack of blinding, small sample size, use of self-reported outcomes, and short intervention periods limit the ability to establish causation confidently. Potential confounders (e.g., training load, diet variations) were not fully controlled.
No Conflicts
No conflicts of interest identified
No conflicts identified.
No funding or conflict of interest statements were found in the provided text. The study uses a commercial product (Dymatize ISO-100) but no industry affiliation is disclosed.
Standing
Who’s using this study?
The videos and claims on this site that lean on this study, and the researchers who wrote it.
1 video from Thomas DeLauer cite this study, drawing 1 claim from it.
- Contradicted
Evidence contradicts this claim.
Evidence
Authored by
4 researchersIf this is your work, this is how we attribute it on Fit Body Science. Jennifer B. Fields is listed as the lead author.