GLP-1 Calorie Calculator

GLP-1 medication cuts appetite, so many people end up eating far less than they realize. This calculator estimates your maintenance calories from your age, sex, height, weight and activity level, then shows three daily targets below it, so you can pick a pace that keeps progress going without dropping lower than your body needs.

Please check your entries: age 18 to 100, weight 80 to 1,000 in your chosen unit, and height 48 to 96 inches or 122 to 244 cm depending on the unit you picked.

Daily planCalories per day

Many people on GLP-1 medication naturally eat less than even the gentlest target here, because appetite suppression does much of the work. Treat these numbers as a ceiling to plan around rather than a quota you must hit, and be cautious with very low intakes: eating too little for too long makes protein harder to fit in and raises the risk of losing muscle along with fat.

Whatever target you choose, protein is the number that protects your muscle. Set yours with the GLP-1 Protein Calculator.

How this estimate works

The calculator first estimates your basal metabolic rate, the energy your body uses at rest, with the Mifflin-St Jeor equation, the formula most widely used for this purpose. For men it is 10 times weight in kilograms, plus 6.25 times height in centimeters, minus 5 times age, plus 5. For women the same formula ends with minus 161 instead of plus 5.

That resting figure is then multiplied by an activity factor to estimate maintenance calories, the amount that would keep your weight roughly steady: 1.2 for sedentary days, 1.375 for light activity, 1.55 for moderate activity and 1.725 for very active days. The three targets simply subtract 250, 500 and 750 calories from maintenance, giving a gentle, a moderate and a faster pace.

Eating too little for too long can backfire. Very low intake makes it harder to hit protein targets, and can leave you tired and short on basic nutrients. These are estimates built from averages, so your true maintenance level may sit a little above or below the figure shown. A few weeks of real results is a better guide than any formula, and your target can move as your weight changes.

Sources and notes. The Mifflin-St Jeor equation (Mifflin et al., American Journal of Clinical Nutrition, 1990) is the standard resting metabolic rate formula used by dietitians and most calorie calculators, and the activity multipliers used here are the conventional ones paired with it. Deficit sizes of 250 to 750 calories a day are the commonly used planning range. None of this predicts how much weight you will lose, and needs vary with health conditions and medication.
Educational tool only. This calculator gives general nutrition information based on a standard formula. It is not medical advice and it is not a personal prescription. Talk to your own doctor, pharmacist or dietitian about your diet, especially if you have diabetes, kidney problems or any other medical condition, or if your appetite is so low that eating feels difficult.

Frequently asked questions

What is the Mifflin-St Jeor equation?

It is the standard formula most dietitians and calorie calculators use to estimate resting metabolic rate, the calories your body burns at rest. It uses your sex, age, weight and height, and this calculator then multiplies the result by an activity factor to estimate your daily maintenance calories.

Why do I feel full on far fewer calories than these targets?

That is the medication working as designed. GLP-1 medicines reduce appetite and slow how quickly the stomach empties, so smaller meals feel filling and hunger between meals fades. Many people naturally eat below their usual maintenance level without trying, which is one reason the weight comes off.

Is a bigger calorie deficit always better?

No. A larger deficit can speed up the scale, but it also raises the risk of losing muscle, feeling tired and missing basic nutrients, especially when total intake is already small. A moderate deficit you can sustain, with enough protein, usually protects muscle and energy better than the most aggressive target.

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