There is no single calorie number that works for everyone on Wegovy, but the clinical trials that led to its approval used a consistent target: a 500-calorie-per-day deficit from whatever your body normally burns. For most women, that works out to roughly 1,200 to 1,500 calories per day. For most men, it lands between 1,500 and 1,800 calories per day. These ranges come from the American Diabetes Association’s obesity management guidelines and align with how Wegovy was studied.
Where the 500-Calorie Deficit Comes From
In the major clinical trials that got Wegovy approved, every participant was instructed to eat about 500 fewer calories per day than their body needed to maintain its current weight. They also aimed for at least 150 minutes of physical activity per week. This combination of a moderate calorie deficit plus exercise was the foundation of the weight loss results you see reported for Wegovy.
The key word here is “deficit,” not a fixed number. A 500-calorie deficit for someone whose body burns 2,400 calories a day means eating around 1,900 calories. For someone whose body burns 1,800 calories a day, it means eating around 1,300. Your starting point depends on your size, age, sex, and how active you are.
How to Estimate Your Starting Number
Your basal metabolic rate, the energy your body uses just to keep you alive at rest, accounts for the largest chunk of what you burn each day. A rough way to estimate your total daily calorie needs is to calculate your BMR and then multiply by an activity factor (typically 1.2 for sedentary people, up to 1.5 or higher for active ones). Many free online calculators do this for you using your age, sex, height, and weight.
As a concrete example: a 35-year-old woman who weighs 165 pounds and is 5 feet 5 inches tall has an estimated BMR of about 1,468 calories per day. If she’s mostly sedentary, her total daily burn is roughly 1,760 calories, making her 500-calorie deficit target around 1,260 calories. That falls right in the 1,200 to 1,500 range the guidelines describe. A taller, heavier, or more active person would land higher.
Why Wegovy Makes Eating Less Feel Easier
Wegovy works on two fronts that directly affect how much you eat. First, it slows the rate at which your stomach empties, so food sits in your stomach longer and you physically feel full sooner during a meal. Second, it acts on appetite centers in the brain, reducing hunger signals and food cravings between meals while amplifying feelings of satisfaction after eating.
This is why many people on Wegovy find they naturally eat less without white-knuckling a calorie restriction. The medication is doing some of the heavy lifting on the appetite side. But that built-in appetite suppression also creates a real risk: some people eat far too little without realizing it.
The Danger of Eating Too Little
Wegovy can suppress appetite so effectively that some people drop to dangerously low intakes. Published case reports describe patients eating only 300 to 600 calories a day, sometimes without recognizing how little they were consuming. The consequences were serious. One patient eating around 400 calories daily lost significant lean muscle mass over just three months. Another who stopped eating and drinking adequately ended up hospitalized with acute kidney injury from dehydration.
Very low calorie diets (under 800 to 1,000 calories per day) are considered safe only under close medical supervision, and they’re not what Wegovy’s clinical trials used. If you consistently eat below 1,200 calories per day, you also face a higher risk of nutritional deficiencies. A large study of over 460,000 adults prescribed GLP-1 medications found that nearly 13% developed a nutritional deficiency within six months, and over 22% had one by 12 months. Multivitamin supplements are worth considering if your intake regularly falls below 1,200 calories or if you’re cutting out entire food groups because of reduced appetite.
Prioritize Protein at Every Meal
When you lose weight on any medication, some of that loss comes from muscle, not just fat. Protein is the main lever you have to protect your muscle mass during weight loss. Current recommendations for people on obesity medications call for 1 to 1.5 grams of protein per kilogram of body weight per day. For someone weighing 200 pounds (about 91 kilograms), that translates to roughly 91 to 136 grams of protein daily.
Older adults over 65 and people with other health conditions should aim for the higher end of that range, around 1.2 to 1.5 grams per kilogram. At a bare minimum, aim for at least 60 to 75 grams of protein per day regardless of your weight. Because Wegovy shrinks your appetite, the meals you do eat need to work harder nutritionally. Protein-rich foods like eggs, Greek yogurt, chicken, fish, beans, and cottage cheese should anchor most of your meals.
Hydration Matters More Than Usual
Reduced appetite on Wegovy often extends to thirst. Some people simply forget to drink because their usual hunger and thirst cues are muted. General guidelines suggest about 11.5 cups of fluid daily for women and 15.5 cups for men, though individual needs vary with activity level, climate, and body size. Fresh fruits and vegetables count toward your fluid intake, but making a conscious effort to drink water throughout the day is important when your body’s natural reminders are quieter than usual.
Dehydration on Wegovy isn’t just uncomfortable. Combined with the nausea or diarrhea some people experience during dose escalation, inadequate fluid intake can become a genuine medical problem, particularly for anyone taking other medications like diuretics.
Practical Calorie Guidelines by Phase
Wegovy is prescribed on a dose-escalation schedule, starting low and increasing over about 16 to 20 weeks. Your appetite suppression tends to intensify as the dose climbs, so your relationship with food will shift over time.
- Early weeks (lower doses): You may not notice a dramatic appetite change yet. A 500-calorie deficit from your estimated maintenance calories is a reasonable target. Focus on building the habit of protein-rich, nutrient-dense meals now, before your appetite drops further.
- Mid-escalation: Appetite suppression typically becomes more noticeable. If you’re struggling to finish meals, prioritize protein and vegetables first, then add other foods. Track your intake loosely to make sure you’re not dipping below 1,200 calories (women) or 1,500 calories (men) on most days.
- Maintenance dose: At the full dose, some people find eating enough to be the real challenge. If you consistently can’t reach your calorie floor, smaller and more frequent meals often help. Calorie-dense but nutritious foods like nuts, avocado, cheese, and olive oil can fill gaps without requiring you to eat large volumes.
What to Watch For
Signs that you’re eating too little include persistent fatigue, hair thinning, feeling cold all the time, dizziness when standing, and muscle weakness. Losing more than about 1% of your body weight per week after the first month is generally faster than recommended and may signal that your calorie intake has dropped too low. Keeping a simple food log, even for just a week or two during dose changes, can reveal patterns you might miss otherwise.