Nutrition
The Nutrition domain tests energy-balance math, deficit design, macronutrient sufficiency, calorie density, hydration, and monitoring. The exam favors practical calculations and client safety over memorized food lists.
Deficit size and rate
One kilogram of body fat stores roughly 7,700 kcal. A 500-kcal daily deficit predicts about 0.45 kg/week, but real loss is slower because of adaptation, reduced NEAT, and logging error. A common target is 0.5–1% of body weight per week, using a 300–750-kcal deficit. Very-low-calorie diets (below about 1,200 kcal for women or 1,500 kcal for men) need medical supervision.
Protein, fiber, and fat
Preserve lean mass with adequate protein: about 1.6–2.2 g/kg/day for resistance-trained clients in a deficit, and at least 1.2–1.6 g/kg/day for general weight loss. Fiber 25–38 g/day supports satiety; fat should not fall so low that hormones and fat-soluble vitamin intake suffer-often 20–35% of calories. Carbohydrate fills the remaining calories and fuels training.
Worked example
An 80-kg client has an estimated TDEE of 2,400 kcal. Set a 500-kcal deficit: 1,900 kcal/day. Protein at 1.6 g/kg = 128 g = 512 kcal. Fat at 25% = 475 kcal ÷ 9 = 53 g. Carbohydrate = 1,900 − 512 − 475 = 913 kcal ÷ 4 = 228 g. Predicted loss is about 0.45 kg/week. Reassess after 2–4 weeks; if the weekly average is flat and adherence is good, trim 100–200 kcal or add steps rather than cutting protein.
Traps
Cut calories so aggressively that adherence collapses; label foods “good” or “bad”; ignore oils, sauces, alcohol, and liquid calories; overestimate exercise burn; let protein or fiber fall too low; change the plan before two weeks of consistent data.