Study analysis · PLoS ONE · 2011
Eating less protein makes you snack 12% more—here's why your chips addiction isn't your fault.
When you eat food with too little protein, your body makes you eat more snacks to try to get enough protein, but you still don't get enough—and you gain weight.
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 showed that when people ate food with less protein, they ate more snacks and calories — but only for four days and only in healthy, lean people. It doesn't prove that eating less protein makes people gain weight over time.
What’s the bottom line?
When people eat food with less protein, their body tries to get more protein by making them eat more food — but not enough to get back to normal protein levels.
How strong is this study?
The researchers did a really good job controlling everything — same food, same taste, same snacks — and made people switch diets randomly. But they only tested 22 people for a few days, so we can't be sure it works for everyone or for a long time.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
59 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=22)+2.1/20
- Follow-up+10/10
100 / 100
54 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervalsno confidence intervals
- 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 554 / 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. This is a randomized controlled trial with controlled manipulation of protein intake, allowing causal inference between protein percentage and energy intake. However, the small sample size (n=22) and short duration (4 days per condition) limit the strength and generalizability of the causal claim.
Key takeaways
- 01
Eating 10% protein instead of 15% made people eat 12% more calories, mostly from snacks like chips.
- 02
Eating 25% protein didn’t make them eat less.
- 03
Yes — eating low-protein diets may cause people to snack more and gain weight over time, even if they don’t feel fuller.
Surprising findings
- Increasing protein to 25% didn’t reduce calorie intake at all.Most people assume more protein = less hunger = fewer calories. But this study shows the body has no mechanism to downregulate intake when protein is high—only when it’s low.
- People ate more food but still consumed less protein overall.The protein leverage hypothesis predicted full compensation—yet protein intake remained lower even after 12% more calories were eaten. The body’s drive to get protein is weaker than expected.
Practical takeaways
Aim for at least 15–20% of your daily calories from protein—especially at breakfast—to prevent mid-morning snack cravings and overeating later.
This study used controlled meals with matched palatability; real-world low-protein diets often include ultra-processed foods, which may amplify the effect.
high confidenceWhy this study matters
Low protein = snack attack
When participants ate a diet where protein made up only 10% of calories (down from 15%), they consumed 12% more total energy—mostly from savory snacks like chips and crackers—over just four days. Their protein intake still dropped, proving the body’s drive to hit a protein target is incomplete.
This explains why low-protein diets (like many processed food diets) lead to constant snacking and weight gain—even if you’re not eating more meals. It’s not willpower, it’s biology.
More protein doesn’t make you eat less
Increasing protein to 25% of calories had zero effect on total energy intake—participants didn’t eat less. This reveals a one-way biological lever: the body compensates for too little protein, but not for too much.
It flips the script on high-protein diet myths—eating extra protein won’t magically suppress appetite. Protein’s power is in preventing overeating, not reducing it.
Hunger spikes after breakfast
On the 10% protein diet, hunger increased 1.6 points between 1–2 hours after breakfast—nearly 3x higher than on the 25% protein diet (0.5 points), with p=0.005. This suggests low protein weakens post-meal satiety signals.
Your mid-morning snack craving isn’t just boredom—it’s your body screaming for protein. Breakfast matters more than you think.
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
When people eat food with less protein, their body tries to get more protein by making them eat more food — but not enough to get back to normal protein levels.
Research results
Eating 10% protein instead of 15% made people eat 12% more calories, mostly from snacks like chips. Eating 25% protein didn’t make them eat less.
What this means - more context
Yes — eating low-protein diets may cause people to snack more and gain weight over time, even if they don’t feel fuller.
To test whether reducing dietary protein promotes overeating via the protein leverage hypothesis in lean adults.
In a randomized controlled trial, lowering protein from 15% to 10% of energy increased daily energy intake by 12% (p=0.02), mainly through savory snacking, but did not fully compensate for reduced protein. Increasing protein to 25% had no effect on energy intake. Hunger increased more after breakfast on the 10% protein diet compared to 25% (p=0.005).
Methods Used
22 lean adults participated in a within-subjects randomized trial with three 4-day phases consuming fixed menus providing 10%, 15%, or 25% energy as protein; foods were matched for palatability and variety; energy and nutrient intake and hunger ratings were measured under ad libitum conditions.
Main Finding
Reducing dietary protein from 15% to 10% increased daily energy intake by 12% ± 4.5% (p=0.02), primarily via savory snacking, but protein intake remained lower, indicating incomplete protein leverage; increasing protein to 25% did not reduce energy intake.
Confidence Level
High: randomized controlled trial with controlled diet, within-subjects design, reported effect sizes and p-values, and direct measurement of intake and hunger.
Study Flags
Red Flags
- •Small sample size (n=22)
- •Short duration (4 days per diet)
- •No long-term weight or metabolic outcomes measured
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
Increasing protein to 25% didn’t reduce calorie intake at all.
Most people assume more protein = less hunger = fewer calories. But this study shows the body has no mechanism to downregulate intake when protein is high—only when it’s low.
Practical Takeaways
Aim for at least 15–20% of your daily calories from protein—especially at breakfast—to prevent mid-morning snack cravings and overeating later.
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 554 / 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 showed that when people ate food with less protein, they ate more snacks and calories — but only for four days and only in healthy, lean people. It doesn't prove that eating less protein makes people gain weight over time.
Strengths
- Randomized controlled trial design with within-subject crossover
- Carefully controlled macronutrient composition and food palatability
- Blinding of participants to diet conditions (assumed due to disguised foods)
Weaknesses
- Small sample size (n=22) limits statistical power
- Blinding status is 'unknown' — participants may have guessed diet conditions
- Short duration (4 days per diet) — cannot assess long-term effects on weight or metabolism
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When people eat food with less protein, their body tries to get more protein by making them eat more food — but not enough to get back to normal protein levels.
Research results
Eating 10% protein instead of 15% made people eat 12% more calories, mostly from snacks like chips. Eating 25% protein didn’t make them eat less.
What this means - more context
Yes — eating low-protein diets may cause people to snack more and gain weight over time, even if they don’t feel fuller.
To test whether reducing dietary protein promotes overeating via the protein leverage hypothesis in lean adults.
In a randomized controlled trial, lowering protein from 15% to 10% of energy increased daily energy intake by 12% (p=0.02), mainly through savory snacking, but did not fully compensate for reduced protein. Increasing protein to 25% had no effect on energy intake. Hunger increased more after breakfast on the 10% protein diet compared to 25% (p=0.005).
Methods Used
22 lean adults participated in a within-subjects randomized trial with three 4-day phases consuming fixed menus providing 10%, 15%, or 25% energy as protein; foods were matched for palatability and variety; energy and nutrient intake and hunger ratings were measured under ad libitum conditions.
Main Finding
Reducing dietary protein from 15% to 10% increased daily energy intake by 12% ± 4.5% (p=0.02), primarily via savory snacking, but protein intake remained lower, indicating incomplete protein leverage; increasing protein to 25% did not reduce energy intake.
Confidence Level
High: randomized controlled trial with controlled diet, within-subjects design, reported effect sizes and p-values, and direct measurement of intake and hunger.
Study Flags
Red Flags
- •Small sample size (n=22)
- •Short duration (4 days per diet)
- •No long-term weight or metabolic outcomes measured
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
Increasing protein to 25% didn’t reduce calorie intake at all.
Most people assume more protein = less hunger = fewer calories. But this study shows the body has no mechanism to downregulate intake when protein is high—only when it’s low.
Practical Takeaways
Aim for at least 15–20% of your daily calories from protein—especially at breakfast—to prevent mid-morning snack cravings and overeating later.
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 554 / 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 showed that when people ate food with less protein, they ate more snacks and calories — but only for four days and only in healthy, lean people. It doesn't prove that eating less protein makes people gain weight over time.
Strengths
- Randomized controlled trial design with within-subject crossover
- Carefully controlled macronutrient composition and food palatability
- Blinding of participants to diet conditions (assumed due to disguised foods)
Weaknesses
- Small sample size (n=22) limits statistical power
- Blinding status is 'unknown' — participants may have guessed diet conditions
- Short duration (4 days per diet) — cannot assess long-term effects on weight or metabolism
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The researchers did a really good job controlling everything — same food, same taste, same snacks — and made people switch diets randomly. But they only tested 22 people for a few days, so we can't be sure it works for everyone or for a long time.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
59 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=22)+2.1/20
- Follow-up+10/10
100 / 100
54 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervalsno confidence intervals
- 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 554 / 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. This is a randomized controlled trial with controlled manipulation of protein intake, allowing causal inference between protein percentage and energy intake. However, the small sample size (n=22) and short duration (4 days per condition) limit the strength and generalizability of the causal claim.
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 2 claims from it.