Weight-Loss Goal and Calorie Deficit Reality Check
A 38-year-old woman (165 cm, 82 kg) works at a desk 9 hours/day and walks 20 minutes three times weekly. She wants to lose 8 kg before a vacation in 8 weeks. She skips breakfast, often eats a large late dinner, drinks two 5-oz glasses of wine most nights, and reports fatigue and frequent afternoon cravings. She has no diagnosed medical conditions, takes no medications, and has a history of yo-yo dieting. She asks you to give her a 1,200-kcal meal plan and a daily 60-minute HIIT workout to speed things up. Her BMI is 30.1.
1. Evaluate the appropriateness of her 8-kg-in-8-weeks goal and calculate the daily energy deficit it would require.
Read the worked answer
8 kg in 8 weeks = 1 kg/week. At about 7,700 kcal per kg, that requires an 1,100 kcal/day deficit, which is aggressive for an 82-kg woman and likely to drive hunger, fatigue, and loss of lean mass. A more appropriate target is 0.5-1% of body weight per week (0.4-0.8 kg/week), or a 400-750 kcal/day deficit, aiming for roughly 4-6 kg in 8 weeks. A 1,200-kcal plan is below what she likely needs and is not a sustainable prescription from a trainer; refer meal planning to a registered dietitian.
2. Identify three behavioral priorities and explain how each supports adherence and body composition.
Read the worked answer
- Add 25-30 g protein at breakfast to blunt afternoon cravings and support lean mass. 2) Shift calories earlier and structure meals and snacks to reduce the large late dinner and evening alcohol; two 5-oz wines add about 200 kcal and can disinhibit eating and disrupt sleep. 3) Increase daily steps and add 2 resistance sessions/week to preserve muscle while in a deficit. Self-monitor intake and weekly average weight. Rationale: these target adherence and body composition, not just the scale.
3. What would you monitor, and when would you refer out?
Read the worked answer
Track weekly average weight, waist, hunger, fatigue, and adherence. If weight is unchanged for 2-3 weeks, reduce intake by 100-200 kcal or add activity. Refer to a registered dietitian for the meal plan, and to a clinician or mental health professional if there are signs of binge eating, depression, dizziness, or if she loses more than 1% of body weight per week sustained.