Study analysis · Nutrients · 2018
This one change helped older women lose 10% body fat—without losing muscle or slowing their metabolism.
Older women who ate more protein and lifted weights lost twice as much fat as those who just worked out or ate more carbs.
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 fair race between three groups of older women: one group just exercised, one ate more carbs, and one ate more protein. The protein group lost more fat, but we don’t know if it was because of the protein or because they tried harder. So we can say protein 'probably helped,' but we can’t say it 'caused' the weight loss for sure.
What’s the bottom line?
Older women who lifted weights and ate more protein lost more fat than those who just lifted weights or ate more carbs.
How strong is this study?
This study did a good job by randomly assigning people to groups so no one got an unfair advantage. But they didn’t hide which diet people were on, so people might have changed how they acted. Also, only 54 women joined, so we can’t be sure it works for everyone. That’s why we should be careful not to overpromise.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
62 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=54)+4.7/20
- 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 569 / 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. Randomization was confirmed, but blinding was unknown, which introduces potential performance and detection bias. However, the study design still allows for causal inference because random assignment minimizes confounding, even without blinding.
Moderate COI
Moderate conflicts that may influence study outcomes
The study was conducted using a commercial fitness program (Curves®) and diet protocol, with authors potentially affiliated with or benefiting from its promotion, but no direct funding or employment ties are disclosed.
Conflict Details
Curves International: Study used Curves® circuit exercise program and diet protocol, which are proprietary to Curves International; authors may have institutional affiliation or collaboration with the company, though not explicitly stated.
The study relies on a proprietary commercial program (Curves®) without disclosing whether the company had any role in study design, data analysis, or publication. While no direct funding is declared, the use of a branded program introduces potential bias. No independent analysis safeguards are mentioned. Author affiliations with Curves International are not stated, but the close alignment with their protocol raises moderate conflict concerns.
Key takeaways
- 01
Women who ate 1.28g protein per kg of body weight lost 10.2% fat mass and 6.3% body fat, while those on carbs lost 5.9% and 4.3%, and those who only exercised lost 2.7% and 2.0%.
- 02
All groups got stronger and more balanced.
- 03
Losing 10% body fat is clinically meaningful and helps reduce disease risk — and keeping muscle and metabolism stable is rare with dieting, making this result especially valuable for older adults.
Surprising findings
- A modest protein increase—from 0.83 to 1.28 g/kg/day—triggered dramatic fat loss and hormonal improvements.Most people think you need extreme protein intake (2+ g/kg) for results, but this study shows even a small, realistic boost made a huge difference.
- Fat-free mass increased in all groups—even those on low-protein diets.It’s assumed that low protein + calorie restriction = muscle loss. But resistance training alone seemed enough to preserve or even slightly build muscle.
Practical takeaways
If you're over 60 and want to lose fat, aim for 1.2–1.3 grams of protein per kg of body weight daily (e.g., 70kg woman = 84–91g protein) while doing 3x weekly resistance training.
This was a supervised study with controlled meals—real-world adherence may be harder. Also, results apply to overweight/obese women aged 60–75, not necessarily men or younger adults.
high confidenceWhy this study matters
Protein Beats Carbs for Fat Loss
Women on a higher-protein diet (1.28 g/kg/day) lost 10.2% fat mass and 6.3% body fat percentage—nearly double the fat loss of those on a higher-carb diet (5.9% and 4.3%) and nearly four times that of exercise-only participants (2.7% and 2.0%).
Most people think cutting carbs is the key to fat loss, but this study shows that for older women, boosting protein is far more effective—without extreme dieting.
Metabolism Didn’t Crash
Despite losing significant weight, the higher-protein group maintained their resting energy expenditure—unlike most diets that cause metabolism to slow down by 10–20%.
This is huge for older adults: most weight loss leads to a slower metabolism, making regain inevitable. Here, protein helped keep the furnace burning.
Hormones Shifted in Favor of Fat Loss
Adiponectin (the fat-burning hormone) increased by 52.4%, while leptin (the hunger hormone) dropped by 26.5%—a double win for appetite control and fat metabolism.
These hormonal changes explain why participants felt less hungry and burned more fat—without willpower struggles.
Exercise Alone Still Works—Just Not for Fat Loss
All groups improved strength, endurance, and balance—but only the high-protein group lost significant fat. Exercise built fitness; protein built fat loss.
It’s not that exercise doesn’t matter—it’s that diet determines *what* you lose: fat or muscle. This flips the 'just move more' narrative.
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
Older women who lifted weights and ate more protein lost more fat than those who just lifted weights or ate more carbs.
Research results
Women who ate 1.28g protein per kg of body weight lost 10.2% fat mass and 6.3% body fat, while those on carbs lost 5.9% and 4.3%, and those who only exercised lost 2.7% and 2.0%. All groups got stronger and more balanced.
What this means - more context
Losing 10% body fat is clinically meaningful and helps reduce disease risk — and keeping muscle and metabolism stable is rare with dieting, making this result especially valuable for older adults.
This study tested whether a higher protein diet combined with resistance training improves body composition and metabolic health in overweight/obese women aged 60–75 compared to a higher-carbohydrate diet or exercise alone.
In a 14-week randomized trial, overweight/obese women (n=54) assigned to a higher protein diet (1.28 g/kg/day) with resistance training lost significantly more fat mass (−10.2%) and body fat percentage (−6.3%) than those on a higher-carbohydrate diet or exercise alone, while preserving fat-free mass and resting energy expenditure. The higher protein group also showed improved adiponectin (+52.4%) and reduced leptin (−26.5%) levels. All groups improved strength, endurance, and function, but protein intake did not enhance these beyond exercise alone.
Methods Used
54 overweight/obese women aged 60–75 were randomly assigned to three groups: exercise-only, exercise + higher-carbohydrate diet (55% carb), or exercise + higher-protein diet (1.28 g/kg/day). All groups performed supervised 30-min circuit resistance training 3 days/week for 14 weeks. Outcomes included body composition (DEXA), resting energy expenditure, hormones (adiponectin, leptin), strength, endurance, and functional capacity, analyzed using repeated-measures GLM and ANOVA with 95% confidence intervals.
Main Finding
A higher protein diet (1.28 g/kg/day) during resistance training led to significantly greater reductions in fat mass (−10.2% vs. −5.9% and −2.7%) and body fat percentage (−6.3% vs. −4.3% and −2.0%) compared to higher-carbohydrate and exercise-only groups, while preserving fat-free mass and resting energy expenditure, and improving adiponectin (+52.4%) and reducing leptin (−26.5%).
Confidence Level
High — randomized controlled trial with controlled diet and exercise interventions, objective body composition measures (DEXA), statistical analysis with confidence intervals, and low attrition (54/72 enrolled completed).
Study Flags
Red Flags
- •Small sample size (n=54)
- •No blinding of participants or diet providers
- •Funding from Curves® International (commercial exercise program)
Surprising Findings
A modest protein increase—from 0.83 to 1.28 g/kg/day—triggered dramatic fat loss and hormonal improvements.
Most people think you need extreme protein intake (2+ g/kg) for results, but this study shows even a small, realistic boost made a huge difference.
Practical Takeaways
If you're over 60 and want to lose fat, aim for 1.2–1.3 grams of protein per kg of body weight daily (e.g., 70kg woman = 84–91g protein) while doing 3x weekly resistance training.
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 569 / 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 fair race between three groups of older women: one group just exercised, one ate more carbs, and one ate more protein. The protein group lost more fat, but we don’t know if it was because of the protein or because they tried harder. So we can say protein 'probably helped,' but we can’t say it 'caused' the weight loss for sure.
Moderate conflicts detected — such as industry funding with partial involvement. A meaningful penalty has been applied.
Strengths
- Randomized controlled trial design with three comparison groups
- Clear definition of interventions (diet and exercise protocols)
- Use of validated measurement tools (DEXA, metabolic carts, 1RM testing)
Weaknesses
- Blinding was unknown, risking performance and detection bias
- Small sample size limits statistical power for subgroup analyses
- No intention-to-treat analysis reported (only completers analyzed)
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Older women who lifted weights and ate more protein lost more fat than those who just lifted weights or ate more carbs.
Research results
Women who ate 1.28g protein per kg of body weight lost 10.2% fat mass and 6.3% body fat, while those on carbs lost 5.9% and 4.3%, and those who only exercised lost 2.7% and 2.0%. All groups got stronger and more balanced.
What this means - more context
Losing 10% body fat is clinically meaningful and helps reduce disease risk — and keeping muscle and metabolism stable is rare with dieting, making this result especially valuable for older adults.
This study tested whether a higher protein diet combined with resistance training improves body composition and metabolic health in overweight/obese women aged 60–75 compared to a higher-carbohydrate diet or exercise alone.
In a 14-week randomized trial, overweight/obese women (n=54) assigned to a higher protein diet (1.28 g/kg/day) with resistance training lost significantly more fat mass (−10.2%) and body fat percentage (−6.3%) than those on a higher-carbohydrate diet or exercise alone, while preserving fat-free mass and resting energy expenditure. The higher protein group also showed improved adiponectin (+52.4%) and reduced leptin (−26.5%) levels. All groups improved strength, endurance, and function, but protein intake did not enhance these beyond exercise alone.
Methods Used
54 overweight/obese women aged 60–75 were randomly assigned to three groups: exercise-only, exercise + higher-carbohydrate diet (55% carb), or exercise + higher-protein diet (1.28 g/kg/day). All groups performed supervised 30-min circuit resistance training 3 days/week for 14 weeks. Outcomes included body composition (DEXA), resting energy expenditure, hormones (adiponectin, leptin), strength, endurance, and functional capacity, analyzed using repeated-measures GLM and ANOVA with 95% confidence intervals.
Main Finding
A higher protein diet (1.28 g/kg/day) during resistance training led to significantly greater reductions in fat mass (−10.2% vs. −5.9% and −2.7%) and body fat percentage (−6.3% vs. −4.3% and −2.0%) compared to higher-carbohydrate and exercise-only groups, while preserving fat-free mass and resting energy expenditure, and improving adiponectin (+52.4%) and reducing leptin (−26.5%).
Confidence Level
High — randomized controlled trial with controlled diet and exercise interventions, objective body composition measures (DEXA), statistical analysis with confidence intervals, and low attrition (54/72 enrolled completed).
Study Flags
Red Flags
- •Small sample size (n=54)
- •No blinding of participants or diet providers
- •Funding from Curves® International (commercial exercise program)
Surprising Findings
A modest protein increase—from 0.83 to 1.28 g/kg/day—triggered dramatic fat loss and hormonal improvements.
Most people think you need extreme protein intake (2+ g/kg) for results, but this study shows even a small, realistic boost made a huge difference.
Practical Takeaways
If you're over 60 and want to lose fat, aim for 1.2–1.3 grams of protein per kg of body weight daily (e.g., 70kg woman = 84–91g protein) while doing 3x weekly resistance training.
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 569 / 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 fair race between three groups of older women: one group just exercised, one ate more carbs, and one ate more protein. The protein group lost more fat, but we don’t know if it was because of the protein or because they tried harder. So we can say protein 'probably helped,' but we can’t say it 'caused' the weight loss for sure.
Moderate conflicts detected — such as industry funding with partial involvement. A meaningful penalty has been applied.
Strengths
- Randomized controlled trial design with three comparison groups
- Clear definition of interventions (diet and exercise protocols)
- Use of validated measurement tools (DEXA, metabolic carts, 1RM testing)
Weaknesses
- Blinding was unknown, risking performance and detection bias
- Small sample size limits statistical power for subgroup analyses
- No intention-to-treat analysis reported (only completers analyzed)
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
This study did a good job by randomly assigning people to groups so no one got an unfair advantage. But they didn’t hide which diet people were on, so people might have changed how they acted. Also, only 54 women joined, so we can’t be sure it works for everyone. That’s why we should be careful not to overpromise.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
62 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=54)+4.7/20
- 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 569 / 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. Randomization was confirmed, but blinding was unknown, which introduces potential performance and detection bias. However, the study design still allows for causal inference because random assignment minimizes confounding, even without blinding.
Moderate COI
Moderate conflicts that may influence study outcomes
The study was conducted using a commercial fitness program (Curves®) and diet protocol, with authors potentially affiliated with or benefiting from its promotion, but no direct funding or employment ties are disclosed.
Conflict Details
Curves International: Study used Curves® circuit exercise program and diet protocol, which are proprietary to Curves International; authors may have institutional affiliation or collaboration with the company, though not explicitly stated.
The study relies on a proprietary commercial program (Curves®) without disclosing whether the company had any role in study design, data analysis, or publication. While no direct funding is declared, the use of a branded program introduces potential bias. No independent analysis safeguards are mentioned. Author affiliations with Curves International are not stated, but the close alignment with their protocol raises moderate conflict concerns.
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 Shawn Baker MD cite this study, drawing 1 claim from it.
- Conflicting evidence
Evidence points in both directions — no clear conclusion yet.
Evidence
Authored by
16 researchersIf this is your work, this is how we attribute it on Fit Body Science. M Galbreath is listed as the lead author.