Standard calculators overestimate what you need after a major loss, because they skip metabolic adaptation. Being 200 calories too high is exactly how slow regain starts. This one includes the adjustment and explains the number it gives you.
CalculatorBuilt for post-GLP-1 maintenanceUpdated July 2026
Before we show you a number
Calorie targets help some people and hurt others. If counting has been tangled up with restriction for you in the past, there is a version of this that works without a single number, and it is genuinely as effective for holding your weight.
Why your old maintenance number is wrong now
The mask comes off
Your daily calorie burn, before and after
Illustrative figures for roughly a 50 lb loss. Your own numbers differ.
The drug never slowed your metabolism. The weight loss did, as any method would: a smaller body burns less, and metabolic adaptation cuts burn further still. While you were on the medication, appetite suppression hid that gap, because you physically could not out-eat it. Off the medication, appetite returns to a body burning hundreds fewer calories than the one that trained your portion instincts. Your old normal is now a surplus. That is the mechanism behind regain: arithmetic, not character. Muscle is the only lever that partly reverses it.
On the medication, you never had to count. Appetite suppression enforced the deficit for you, silently. That is the part worth understanding before you look at any number: the drug was hiding a gap, not creating one.
Here is the sequence, and it is the most important explainer on this site:
The drug never slowed your metabolism. Slowed stomach emptying is transit time, not energy burn. The weight came off because appetite was muted and you ate less.
The weight loss slowed your metabolism, as any method would. A smaller body burns less, and metabolic adaptation cuts burn further still, a defensive response that the Biggest Loser six-year follow-up showed persists for years.
On the drug, that slowdown was invisible. You physically could not out-eat your reduced burn while appetite was suppressed.
Off the drug, the mask comes off all at once. Appetite returns to normal or above, aimed at a body burning 300 to 500 fewer calories a day than the one that trained your portion instincts.
That is the entire mechanism behind how fast regain can start. Arithmetic, arriving suddenly. Not character.
The math this calculator runs
Step
What it does
1. BMR
Mifflin-St Jeor equation from weight, height, age and sex. Your resting burn.
2. Activity multiplier
1.2 sedentary through 1.725 very active, giving total daily expenditure.
3. Adaptation adjustment
Minus 10% if you lost more than 10% of your starting weight. The step nearly every other calculator omits.
4. Output
A maintenance target. Not a deficit. The goal is holding, not losing again.
Worked example: 52-year-old woman, 150 lb, 5 foot 5, lightly active, lost 60 lb. BMR 1,290 → times 1.375 = 1,774 → minus 10% = about 1,600 calories. That 174-calorie difference is the whole ballgame over a year.
Self-correction beats precision
These equations are accurate to roughly plus or minus 10%, so treat the output as a starting hypothesis rather than a fact. The method that actually works:
Eat at the estimate for three weeks
Weigh daily, read only the seven-day average
Trend rising when you wanted flat? Drop 100 calories. Falling when you did not want it to? Add 100.
Repeat. After three cycles your number is empirical, which beats any formula
The trend line is what makes the estimate self-correcting. Without it you are guessing forever; with it, an imperfect starting number is completely fine.
A word about calorie counting and this population
Many people arriving here have decades of diet history, and for some of them counting is genuinely harmful. Two rules built into this tool: it will never display a target below 1,200 calories for women or 1,500 for men (if the math produces less, you get a referral instead of a number), and it offers a complete no-numbers path before you enter anything. Protein first, plate structure, and a watched trend hold weight without a single calorie logged.
The two things that matter more than this number
Calories are one lever and not the strongest. If you only do two things after stopping, do these: hit a protein floor of roughly 1.6g per kg of goal weight split across three meals, and lift something heavy two or three times a week to protect the muscle that sets the number this calculator estimates. The full case is in the muscle loss guide, and the broader plan is in how to not gain the weight back.
Frequently asked questions
How many calories should I eat to maintain weight after stopping Ozempic?
It depends on your size, age, activity and how much you lost, but the important correction is that it is lower than standard calculators suggest. After losing more than 10% of your body weight, metabolic adaptation means typical equations overestimate your needs, so this calculator applies a 10% downward adjustment. For a common example, a 52-year-old woman at 150 lb and 5 foot 5 who is lightly active and lost 60 lb lands near 1,600 calories rather than the roughly 1,775 a standard calculator would return.
Why do I burn fewer calories after losing weight?
Two stacked effects. A smaller body simply requires less energy to move and maintain. On top of that, metabolic adaptation means the body reduces energy expenditure beyond what the size change predicts, a defensive response to sustained weight loss that persists for years (documented in the Biggest Loser six-year follow-up). Together they commonly total 300 to 500 fewer calories a day after a large loss, and any muscle lost on the way down deepens the gap because lean tissue is metabolically active.
Did the medication slow my metabolism?
No, and this distinction matters. GLP-1 medications work by muting appetite so you eat less, and by slowing stomach emptying, which is transit rather than energy burn. The weight loss slowed your metabolism, exactly as any method of losing that much weight would. What the drug did was hide the gap: while appetite was suppressed you could not physically out-eat your reduced burn, so you never felt it. When the drug clears, the mask comes off and your old portion instincts are suddenly a surplus.
How accurate are calorie calculators?
Roughly plus or minus 10% at best, which on a 1,700 calorie target is a 170 calorie error in either direction, enough to cause slow gain or slow loss. That is why the method here is empirical rather than mathematical: use the estimate as a starting point, weigh daily for three weeks, read the smoothed trend, and adjust by 100 calories based on what actually happened. Three cycles of that beats any equation.
Should I eat at a deficit after stopping a GLP-1?
Generally no, and this calculator deliberately does not produce a deficit. The goal after stopping is holding your result, not continuing to lose. Deficits after a major loss increase food noise, accelerate muscle loss, and raise the odds of the restrict-then-rebound cycle that causes regain in the first place. If you want to lose more weight, that is a conversation for your prescriber or a dietitian, not a target this tool should hand you.
What if I do not want to count calories?
Then do not, and know that you are not settling for less. The tool offers a no-numbers path: protein first at every meal, a simple plate structure of half vegetables, quarter protein, quarter starch, three eating occasions a day, and a watched weight trend. That approach approximates maintenance intake automatically and carries none of the risk that counting poses for people with restriction histories. It is genuinely as effective for holding weight.
Sources
Mifflin-St Jeor equation: Mifflin MD et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr, 1990.
Biggest Loser 6-year follow-up: Fothergill E et al. Persistent metabolic adaptation 6 years after "The Biggest Loser" competition. Obesity, 2016.
STEP-1 extension: Wilding JPH et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide. Diabetes Obes Metab, 2022.
SURMOUNT-4: Aronne LJ et al. Continued treatment with tirzepatide for maintenance of weight reduction. JAMA, 2024.
Morton et al. protein meta-analysis: Morton RW et al. Systematic review, meta-analysis and meta-regression of protein supplementation and resistance training (n=1,863). Br J Sports Med, 2018.
Linked citations open on PubMed or DailyMed, both run by the US National Institutes of Health. Where a claim on this page comes from reporting or clinical commentary we could not resolve to a stable public record, it is listed above without a link rather than pointed at an approximation.
