Thermic-effect

Protein's role in weight loss operates through three mechanisms: thermic effect (~150 kcal/day at 150g protein), satiety (Weigle 2005: −440 kcal/day at 30% protein), and lean mass preservation (Stiegler 2006: reduces lean mass loss from 25% to 8–12% of weight lost). Target is 1.6–2.0g/kg/day. This article covers the evidence and practical food sources.

A breakfast of 2 eggs (340 kcal) vs. an isocaloric bagel reduces lunch calorie intake by approximately 400 kcal in RCT evidence (Vander Wal 2008). Eggs' satiety advantage comes from high protein density (13g per large egg), low energy density, and yolk composition. This article reviews the mechanism and evidence.

The claim that eating frequently 'boosts metabolism' is based on the thermic effect of food — but the evidence shows meal frequency has little effect on total daily energy expenditure. This article examines what the research actually demonstrates about meal timing, meal frequency, and metabolic rate.

Protein has the highest thermic effect of any macronutrient (20–30% of protein calories burned during digestion) and produces the largest passive reduction in appetite of any dietary intervention — 440 kcal/day spontaneous reduction when protein increases from 15% to 30% of energy (Weigle 2005 RCT). This article reviews what high-protein foods actually do to metabolism and weight.

A 'metabolic boost' refers to increasing one or more components of total daily energy expenditure (TDEE): resting metabolic rate (60–70%), NEAT (15–30%), thermic effect of food (8–10%), or exercise (0–15%). The highest-impact evidence-supported interventions are protein intake (−440 kcal/day satiety + TEF), resistance training (lean mass gain), and NEAT increase (300–400 kcal/day from steps). This article explains the science.