Daily calories and macros tuned for reduced appetite — protect lean mass while you lose weight.
I'm on a GLP-1 medication
Increases protein target to preserve lean mass during rapid weight loss
Daily Calories
1,600
target deficit applied
Protein
145g
~580 cal · 36%
Fat
53g
~480 cal · 30%
Carbs
135g
~540 cal · 34%
On GLP-1 medications, hitting your protein target is more important than hitting calories exactly. Eat protein first at every meal.
Per-meal breakdown
Meal
Calories
Protein
Carbs
Fat
Not medical advice. This calculator is educational. Always work with your prescribing clinician or a registered dietitian when adjusting nutrition on a GLP-1 medication — especially regarding electrolytes, hydration, and nutrient deficiencies.
Why GLP-1 users need a different macro plan
GLP-1 receptor agonists — semaglutide (Ozempic, Wegovy), tirzepatide (Mounjaro, Zepbound), and similar — reduce appetite by 30–50% in most patients. That's exactly how they cause weight loss. But the same mechanism creates two nutritional problems standard "calories in / calories out" calculators ignore:
Lean mass loss. Published trials show 25–40% of weight lost on GLP-1s can be muscle when protein is inadequate. Higher protein (1.4–1.8 g/kg body weight) plus resistance training cuts this dramatically.
Undereating. Appetite suppression makes it easy to drop below 1,000 calories accidentally. That accelerates lean mass loss, tanks energy, and stalls progress when the body downregulates metabolism.
This calculator handles both: it sets a moderate deficit (not aggressive), prioritizes protein in grams (not as a percentage), and floors calories at a safe minimum.
How the calculation works
1. Basal metabolic rate (BMR) from the Mifflin-St Jeor equation — the most accurate general-population BMR formula.
2. Total daily energy expenditure (TDEE) by multiplying BMR × activity factor.
3. Target calories = TDEE plus or minus your goal deficit/surplus.
4. Protein set in grams per kg of body weight (NOT as a percentage of calories — this is the key difference for GLP-1 users).
5. Fat set at minimum 0.6 g/kg for hormone function.
6. Carbs fill the remaining calories.
Practical eating rules on a GLP-1
Protein first, every meal. Your appetite will fade halfway through eating. If protein is already on your plate first, you'll hit your target before you stop feeling hungry.
4–5 smaller meals beat 3 big ones. GLP-1s slow gastric emptying. Large meals cause nausea or vomiting in many patients.
Hydrate aggressively. Reduced food intake also reduces water intake (food is ~20% of daily fluid). Aim for 80+ oz daily.
Lift weights 2–3× per week. Resistance training is the single biggest factor in preserving muscle during weight loss on any GLP-1 protocol.
Don't skip meals. Even when you're not hungry. Skipping makes nausea worse next dose.
FAQ
Why is protein more important on GLP-1 medications?
Rapid weight loss from any cause breaks down muscle along with fat. Trials of semaglutide and tirzepatide show 25–40% of weight lost can be lean mass when protein intake is inadequate. Higher protein (1.4–1.8 g per kg body weight) plus resistance training reduces lean mass loss significantly. That's why this calculator sets protein in grams per kg, not as a percentage of calories.
How many calories should I eat on a GLP-1?
Your TDEE minus a moderate deficit — usually 500–750 calories per day for steady fat loss. The calculator caps deficits to prevent dangerous undereating. Avoid going below 1,200 calories (women) or 1,500 (men) without medical supervision.
What should I eat first at each meal?
Protein first, then vegetables, then carbs/fats. Appetite fades quickly on GLP-1s, so prioritizing protein at the start of each meal ensures you hit your daily target before you stop feeling hungry. A good first bite: lean meat, fish, eggs, Greek yogurt, or a protein shake.
Should I eat 3 meals or 5 small ones?
Most GLP-1 users do better with 4–5 smaller meals because the medication slows gastric emptying, making large meals uncomfortable. The calculator splits across 4 meals by default — switch to 5 or 6 in the dropdown if you're getting nauseated after meals.
Will I lose weight slower if I eat more protein?
No. Higher protein actually improves fat loss vs. lean mass loss at the same calorie deficit. The scale moves at roughly the same rate, but the weight you lose is more fat and less muscle — meaning better body composition and a higher metabolism at the end of your weight loss phase.
What about fiber, vitamins, electrolytes?
All become harder to hit at lower calorie intakes. Aim for 25–35g fiber daily (vegetables, berries, beans, oats). Consider a basic multivitamin, and if you're getting constipated or fatigued, talk to your clinician about magnesium, sodium, and potassium intake. Many GLP-1 patients also benefit from a daily probiotic.