What is TDEE and why does it matter?
TDEE — Total Daily Energy Expenditure — is the total number of calories your body burns in a day, accounting for your basal metabolic rate (BMR) plus physical activity. It's your maintenance calorie level: eating exactly at TDEE means your weight stays the same.
On GLP-1 medications, your appetite is dramatically suppressed — most users naturally eat 30–50% fewer calories than before. For many people this creates an accidental deficit that's actually too large, dropping below 1,000 calories per day without realizing it. This triggers muscle loss, nutrient deficiencies, fatigue, and metabolic adaptation that makes long-term weight maintenance harder.
The GLP-1 paradox: The medication does the work of suppressing your appetite — you don't need to aggressively restrict calories on top of it. A moderate 500–750 calorie deficit from TDEE is optimal. Larger deficits accelerate muscle loss without proportionally increasing fat loss.
Minimum calorie floors
Regardless of what any calculator shows, clinical guidelines establish hard minimums to prevent serious health consequences from inadequate nutrition:
| Group | Minimum daily calories | Why |
|---|---|---|
| Women (general) | 1,200 cal/day | Prevent nutrient deficiency and excessive muscle loss |
| Men (general) | 1,500 cal/day | Higher lean mass requires more baseline nutrition |
| Active women | 1,400–1,600 cal/day | Fuel exercise and recovery |
| Active men | 1,800–2,000 cal/day | Fuel exercise and preserve muscle |
If your GLP-1 medication suppresses your appetite below these levels, prioritize eating enough protein and calories even if you're not hungry. This is one of the most common challenges for GLP-1 users and why a registered dietitian can be valuable.
Macronutrient targets on GLP-1
With reduced total calories, how you distribute those calories matters more than ever. The recommended macro split for GLP-1 users differs from general weight loss recommendations:
- Protein (30–35% of calories): Higher than typical weight loss recommendations to compensate for the muscle-sparing challenge of a large appetite-driven deficit.
- Fat (30–35% of calories): Dietary fat supports hormone function and fat-soluble vitamin absorption. Don't go ultra-low-fat on GLP-1.
- Carbohydrates (30–40% of calories): Lower than standard Western diets, but not keto. Prioritize fiber-rich carbs (vegetables, legumes, whole grains) for gut health.