Protein shakes make your body burn a little more calories at rest and after eating, but this doesn’t help you keep the weight off.
Scientific Claim
Protein supplementation increases diet-induced thermogenesis by approximately 30 kJ/2.5 h and resting energy expenditure by 243 kJ/day compared to a control supplement in obese adults after weight loss, despite no effect on weight maintenance.
Original Statement
“Compared with the control, protein supplementation resulted in higher DIT (∼30 kJ/2.5 h) and resting energy expenditure (243 kJ/d)”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
probability
Can suggest probability/likelihood
Assessment Explanation
The RCT design supports causal inference for these physiological outcomes. The abstract reports specific effect sizes and statistical comparisons, justifying probabilistic language.
More Accurate Statement
“Protein supplementation probably increases diet-induced thermogenesis by approximately 30 kJ/2.5 h and resting energy expenditure by 243 kJ/day compared to a control supplement in obese adults after weight loss, despite no effect on weight maintenance.”
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Randomized Controlled TrialLevel 1bIn EvidenceCausal effect of specific protein types on energy expenditure and thermogenesis in post-weight-loss adults.
Causal effect of specific protein types on energy expenditure and thermogenesis in post-weight-loss adults.
What This Would Prove
Causal effect of specific protein types on energy expenditure and thermogenesis in post-weight-loss adults.
Ideal Study Design
A double-blind RCT of 120 obese adults (BMI 28–38) randomized to 48 g/day whey, soy, or placebo, with 24-hour indirect calorimetry and meal tests at baseline and week 24, controlling for body composition and physical activity.
Limitation: Short-term measurement may not reflect long-term metabolic adaptation.
Prospective Cohort StudyLevel 2bLong-term association between protein intake and sustained increases in energy expenditure after weight loss.
Long-term association between protein intake and sustained increases in energy expenditure after weight loss.
What This Would Prove
Long-term association between protein intake and sustained increases in energy expenditure after weight loss.
Ideal Study Design
A 2-year cohort study of 500 adults who lost ≥10% body weight, measuring daily protein intake via food diaries and energy expenditure via doubly labeled water at 6-month intervals.
Limitation: Cannot isolate protein’s effect from other dietary or behavioral changes.
Cross-Sectional StudyLevel 3Correlation between habitual protein intake and resting energy expenditure in weight-stable individuals.
Correlation between habitual protein intake and resting energy expenditure in weight-stable individuals.
What This Would Prove
Correlation between habitual protein intake and resting energy expenditure in weight-stable individuals.
Ideal Study Design
A cross-sectional analysis of 1000 adults with stable weight, measuring habitual protein intake (food frequency) and resting metabolic rate via indirect calorimetry, adjusting for fat-free mass and age.
Limitation: Cannot determine direction of causality or temporal sequence.
Evidence from Studies
Supporting (1)
The study found that taking extra protein after losing weight burns a bit more calories at rest and after meals, just like the claim says — even though it didn’t help people keep the weight off.