You have just received your first injection of semaglutide (Ozempic, Wegovy), tirzepatide (Mounjaro), or liraglutide (Saxenda), and nobody really explained what to put on your plate. Welcome to the great nutritional silence surrounding GLP-1 analogs. The doctor prescribes, the pharmacist dispenses, the tracking app weighs your food, but in between there remains this strange void: what should you eat when your appetite drops by 30 percent, when every bite can trigger nausea, when the scale goes down but your hair falls out too?
This guide is designed to fill that void. It is meant just as much for people who are starting treatment and dread the first weeks as for those in the maintenance phase who want to avoid the classic pitfalls: muscle loss, deficiencies, weight regain after stopping. We cover the three most commonly prescribed molecules (semaglutide, tirzepatide, liraglutide), with a specific macro protocol, a 7-day meal plan tested in clinical practice, validated strategies for managing each common side effect, and an often-forgotten chapter: how to avoid regaining the weight after you stop.
You will find precise figures (grams of protein per kilo, liters of water, injection timing windows), concrete food lists available in any supermarket, and an action plan you can apply starting tomorrow morning. No useless medical jargon, no miracle promises, just what actually works when you want to turn a GLP-1 treatment into lasting, healthy weight loss.
How GLP-1s work and why nutrition matters so much
GLP-1 (glucagon-like peptide 1) is a gut hormone naturally secreted after meals. It plays three main roles: stimulating insulin production when blood glucose is high, slowing the release of glucagon (the hormone that raises blood sugar), and slowing gastric emptying to prolong the feeling of fullness. The pharmacological analogs (semaglutide, tirzepatide, liraglutide) reproduce and amplify this action, with a much longer half-life than the natural hormone.
Tirzepatide goes even further: it acts on both the GLP-1 receptor and the GIP receptor (glucose-dependent insulinotropic polypeptide), which explains its superior efficacy observed in clinical trials (average weight loss of 20 to 22 percent at 72 weeks according to the SURMOUNT studies published in The New England Journal of Medicine). Semaglutide at the obesity dose (Wegovy 2.4 mg) produces an average of 15 percent weight loss over 68 weeks (STEP-1 study, NEJM 2021). Liraglutide remains effective but less powerful (5 to 8 percent loss on average).
This pharmacological action has three major nutritional consequences that on their own justify a dedicated guide. First, appetite drops dramatically: most patients report a spontaneous decrease in caloric intake of 20 to 35 percent. This drop is not trivial. Without monitoring, it mechanically leads to insufficient protein intake and micronutrient deficiencies. Second, the slowed gastric emptying creates increased intolerance to cooked fats, fried foods, aged cheeses, and large volumes. Poorly managed, this slowdown causes nausea, reflux, and sulfur burps. Third, rapid weight loss exposes you to significant muscle loss if protein and movement are lacking.
It is precisely for these three reasons that a structured eating plan multiplies the effectiveness of the treatment while reducing its drawbacks. Clinical guidance converges on one point: the GLP-1 analog is not a substitute for nutritional follow-up, it is an amplifier that demands more dietary rigor, not less. That is the whole purpose of the rest of this guide. To understand how the Cetona platform translates these principles into a daily plan, see our GLP-1 page.
Macros and calories on GLP-1
The first instinct when appetite drops is to eat less. That is precisely the mistake to avoid. On GLP-1 treatment, the goal is not to maximize the calorie deficit: it is to ensure that every calorie you eat is useful, starting with protein.
Calorie target: neither starvation nor excess
For women, the useful range is between 1,200 and 1,600 kcal per day. For men, between 1,500 and 1,900 kcal. Staying long term below 1,200 kcal without medical supervision exposes you to sarcopenia (pathological muscle loss), micronutrient deficiencies, hair loss, chronic fatigue, and a metabolic slowdown that will make post-treatment stabilization very difficult. These thresholds are aligned with established reference points for supervised low-calorie diets.
Protein: the non-negotiable pillar
The protein target is between 1.2 and 1.6 g per kilogram of target body weight. For a woman of 78 kg aiming for 65 kg, that represents 78 to 105 g of protein per day. For a man of 95 kg aiming for 80 kg, 96 to 130 g per day. This range is higher than general recommendations (0.83 g/kg/day) because rapid weight loss amplifies muscle breakdown and requires a higher intake to preserve lean mass, as clinical nutrition bodies emphasize.
Timing matters as much as quantity. Four servings of 25 to 35 g of protein trigger four waves of muscle protein synthesis, whereas a single large serving saturates the mechanisms after 30 to 40 g and wastes the rest as energy. In practice: protein-rich breakfast, protein-rich lunch, protein snack around 4 p.m., protein-rich dinner. Skyr, fat-free quark, eggs, chicken breast, white fish, silken tofu, tempeh, slow-cooked legumes, quality protein powders. To go further, see our GLP-1 protein calculator and the dedicated article on Ozempic and muscle loss.
Fats: 40 to 50 percent of intake, but which ones
On GLP-1, fats cooked at high temperature and fried foods worsen nausea by overburdening the slowed digestion. The rule is simple: favor raw or gently cooked fats (olive oil, avocado, sardines, mackerel, almonds, chia seeds, occasional clarified butter). Avoid fatty cured meats, large quantities of aged blue cheeses, and ready-made meals in industrial sauces.
Carbs: 15 to 25 percent, low glycemic index exclusively
Strict keto (under 30 g/day) is counterproductive on GLP-1 because it worsens the already frequent constipation. The Cetona target is between 15 and 25 percent of intake, or 60 to 100 g of carbs per day, exclusively low glycemic index: green vegetables, berries (blueberries, raspberries, strawberries), well-cooked legumes in the maintenance phase (red lentils, chickpeas), small portions of sweet potato, quinoa. To avoid: white bread, white pasta, large quantities of white rice (except as a fallback during severe nausea), fast sugars, fruit juices.
Hydration: 2 to 2.5 liters, spread out
The sensation of thirst drops on GLP-1, which leads to silent dehydration and amplifies constipation, fatigue, and headaches. Aim for 2 to 2.5 liters spread over the day, never drunk all at once (which causes gastric distension and nausea). Water, ginger or mint infusions, homemade clear broths. Adding a pinch of unrefined salt and half a lemon to the first glass in the morning covers the often-neglected sodium and potassium needs. Coffee remains possible but never on an empty stomach (gastric irritation) and limited to 2 cups per day.
Sample 7-day meal plan
This weekly plan is designed for the maintenance phase (from around week 8). For the escalation phase (weeks 1 to 4), reduce portions by 30 percent and favor soft textures, lukewarm temperatures, and splitting meals into 5 to 6 mini-meals. All meals are calculated to reach 25 to 35 g of protein per serving, with ingredients available in most supermarkets (Walmart, Whole Foods, Tesco, Kroger). To generate a personalized GLP-1 shopping list by supermarket, our app does it automatically.
Monday
- Morning: 2 eggs scrambled in olive oil, 100 g fat-free quark, 50 g raspberries, black coffee. About 28 g of protein.
- Midday: Steamed cod fillet 130 g, steamed broccoli, 60 g quinoa, 1/2 avocado. 31 g of protein.
- 4 p.m.: Plain skyr yogurt 150 g + 10 almonds. 18 g of protein.
- Evening: Spinach omelette (3 eggs), green salad, 1 tbsp olive oil. 24 g of protein.
Tuesday
- Morning: Skyr 200 g + chia seeds + blueberries. Coffee. 26 g of protein.
- Midday: Grilled chicken breast 120 g, sauteed zucchini, cooked red lentils 80 g. 35 g of protein.
- 4 p.m.: 1 hard-boiled egg + 1 slice of cooked ham. 14 g of protein.
- Evening: Steamed salmon 130 g, asparagus, steamed sweet potato 100 g. 28 g of protein.
Wednesday
- Morning: Oatmeal pancakes 30 g + 1 scoop of whey + 1 egg, raspberries. 28 g of protein.
- Midday: Water-packed tuna salad 1 can + hard-boiled egg + tomatoes + 1/2 avocado + olive oil. 33 g of protein.
- 4 p.m.: Fat-free quark 150 g + cinnamon. 16 g of protein.
- Evening: Grilled firm tofu 150 g, homemade ratatouille, 1 tbsp olive oil. 22 g of protein.
Thursday (injection day: anti-nausea recipes)
- Morning: Clear chicken broth + poached egg + 1 slice of toasted whole-grain bread. 12 g of protein.
- Midday: White rice 50 g + steamed white fish 100 g + steamed carrots, freshly grated ginger. 24 g of protein.
- 4 p.m.: Ripe banana + 1 tbsp almond butter. 8 g of protein.
- Evening: Smooth zucchini soup + 100 g fat-free quark with a drizzle of honey. 18 g of protein.
Friday
- Morning: Egg tortilla (3) + smoked salmon 50 g + chives. 30 g of protein.
- Midday: Buddha bowl quinoa 60 g + cooked chickpeas 80 g + cucumber + feta 40 g + olive oil. 26 g of protein.
- 4 p.m.: Protein smoothie: 1 scoop whey + 200 ml almond milk + raspberries. 25 g of protein.
- Evening: Steamed sea bream fillet 140 g, spinach in light cream, 1 tbsp olive oil. 32 g of protein.
Saturday
- Morning: Fat-free Greek yogurt 200 g + homemade sugar-free granola 30 g + blueberries. 22 g of protein.
- Midday: Ground beef 5 percent fat 120 g, green beans, sweet potato 80 g. 30 g of protein.
- 4 p.m.: 2 hard-boiled eggs + cucumber. 12 g of protein.
- Evening: Curry-sauteed tempeh 130 g + roasted cauliflower + basmati rice 50 g. 24 g of protein.
Sunday
- Morning: 2 fried eggs, 1 slice of cooked ham, cherry tomatoes, 1/2 avocado. 24 g of protein.
- Midday: Roast veal 130 g, braised fennel, green lentils 80 g. 36 g of protein.
- 4 p.m.: Cottage cheese 150 g + raspberries. 18 g of protein.
- Evening: Pumpkin veloute + sauteed shrimp 150 g + 1 tbsp olive oil. 28 g of protein.
This weekly plan remains an example. A full personalization accounting for target weight, the molecule, the titration phase, dietary restrictions, and your usual supermarket takes three minutes through our intake quiz. For specific anti-nausea recipes and a detailed 7-day Ozempic menu, see our dedicated guides.
Common side effects and how nutrition helps
Nausea (weeks 1 to 6 especially)
This is the most common side effect (affecting 40 to 50 percent of patients at initiation, according to the prescribing information for the medications involved). Direct cause: the slowed gastric emptying that prolongs the presence of food in the stomach and stimulates the nausea receptors. Nutritional solutions: split into 5 to 6 mini-meals rather than 3 large ones, eat slowly (put the fork down between each bite), favor lukewarm or cold temperatures (piping-hot dishes amplify nausea), avoid fried foods, fatty sauces, and aged cheeses. Fresh ginger (grated into an infusion or added to a broth) has proven clinical benefit against nausea (Cochrane meta-analyses). See our complete guide Ozempic nausea: what to do.
Constipation (affects 25 to 30 percent of patients)
Cause: slowed transit linked to the braked gastric emptying, a mechanical drop in food volume, and silent dehydration. Solutions: 25 to 30 g of fiber per day (soluble fibers such as oats, chia seeds, and psyllium as a priority; insoluble fibers via green vegetables and apple skin), 2 to 2.5 liters of water spread out, post-meal movement (a 10 to 15 minute walk after each meal). Validated unblocking foods: 2 ripe kiwis per day, lukewarm soaked prunes, plain yogurt with chia. Increase fiber gradually so as not to create bloating. See our dossier Ozempic constipation solution.
Fatigue (often around week 2 to 4)
Multifactorial: involuntary undereating, reactive hypoglycemia, dehydration, deficiencies (iron, vitamin D, B12). Nutritional solutions: never drop below 1,200 kcal for a woman, structure stabilizing snacks every 3 to 4 hours (hard-boiled egg, skyr, quark), cover iron via lean red meats, sardines, lentils paired with vitamin C. Systematic vitamin D supplementation to validate with your doctor. Our article Ozempic fatigue details the 7 main causes.
Muscle loss and hair loss (medium-term risk)
Recent studies published in Diabetes, Obesity and Metabolism and The Lancet show that up to 40 percent of total weight loss on GLP-1 can be muscle without nutritional countermeasures. The hair loss that follows does not come from the medication but from deficiencies in protein, iron, zinc, and biotin. Preservation protocol: 1.2 to 1.6 g of protein per kilo, strength training 2 to 3 times per week (bodyweight, resistance bands, or dumbbells depending on level), vitamin D + B12 supplementation if a deficiency is measured, a reasonable rate of loss (0.5 to 1 percent of body weight per week, no more). The hollowed face (sometimes called Ozempic face) results from the same muscle loss combined with the loss of subcutaneous fat and is prevented by the same levers.
Acid reflux and sulfur burps
Less documented but frequent effects. Cause: the slowed emptying lets certain foods (eggs, red meats, cabbage) ferment longer, producing sulfur compounds. Solutions: avoid late meals (dinner 3 hours before bed), raise the head of the bed, split meals, limit raw cruciferous cabbages. Chewing fennel after meals also reduces fermentation.
Common eating mistakes
Skipping meals because your appetite has disappeared. The most costly mistake. No appetite does not mean no need. Skipping breakfast and lunch to nibble only a yogurt in the evening guarantees a protein deficit, muscle loss, and fatigue. Setting alarms in the first weeks helps with structure.
Falling into over-restriction. Many people think that by eating 800 kcal/day, they maximize results. Wrong. The metabolism collapses, the body catabolizes muscle, hair falls out, and regain after stopping is guaranteed. The target remains a moderate deficit (300 to 500 kcal/day) sufficient for 0.5 to 1 percent weekly loss.
Neglecting protein. A serving of green salad with a little chicken does not make a protein meal. 25 to 35 g of protein per serving is 130 g of chicken or 200 g of skyr or 4 eggs. Physically weigh them the first two weeks to calibrate your eye.
Continuing alcohol as before. Even a glass of wine on an empty stomach can trigger reactive hypoglycemia and amplify nausea for 12 hours. Many patients spontaneously develop an aversion; that is a good thing, do not fight it.
Ignoring digestive signals. Persistent nausea, repeated vomiting beyond 48 hours, acute epigastric pain, or no bowel movement for more than 5 days require a medical consultation. No panic, but no wait-and-see either: these signals can indicate pancreatitis or a partial obstruction, rare but documented in the safety information.
Maintaining weight after stopping treatment
This is the topic nobody talks about enough. The available studies (notably the STEP-4 follow-up published in JAMA 2022) show that on stopping semaglutide, about 68 percent of patients regain two-thirds of the weight lost within the following year. This figure is terrifying, but it is explainable: without structural habit change, without muscle preservation, and without a transition plan, the body returns to its previous set point.
A transition protocol drastically reduces this risk. The basic rule: gradual weaning over 8 to 12 weeks (monthly dose reduction rather than abrupt stopping), maintaining high protein intake (1.2 to 1.6 g/kg kept indefinitely), continuing strength training 2 to 3 times per week, and switching to monthly nutritional follow-up for at least 12 months post-stopping.
Post-GLP-1 eating is not a return to before treatment, it is a new baseline. The principles remain identical (protein density, hydration, quality fats, low glycemic index carbs), simply with slightly increased portions to compensate for satiety returning to normal. It is precisely to support this critical phase that we are developing a continuation plan module in the app. In the meantime, see our GLP-1 alternatives and continuation guide.
Frequently asked questions (FAQ)
1. How many calories per day on GLP-1 treatment?
The useful range: 1,200 to 1,600 kcal for women, 1,500 to 1,900 kcal for men. Never below 1,200 kcal without medical follow-up. The challenge is not to cut more, it is to guarantee the nutritional density of every bite.
2. How much protein to eat per day on Ozempic or Wegovy?
Between 1.2 and 1.6 g of protein per kilo of target weight, spread over 4 servings of 25 to 35 g. For a woman of 78 kg aiming for 65 kg, about 90 to 105 g per day.
3. How long does nausea last on Ozempic?
Peak between week 2 and week 4, then improvement in 7 to 14 days in most cases. Split, lukewarm meals low in cooked fats shorten this phase.
4. Should you follow a ketogenic diet with Ozempic?
No. Strict keto worsens constipation. Our protocol maintains 15 to 25 percent low glycemic index carbs, enough for transit.
5. Can you lose muscle on Ozempic?
Yes, up to 40 percent of total loss without countermeasures. Reaching the protein target and doing strength training 2 to 3 times per week brings this figure under 15 percent.
6. Is alcohol compatible with a GLP-1 treatment?
In very small occasional doses and never on an empty stomach. Many patients develop a spontaneous aversion.
7. What to eat on injection days?
Lukewarm meals, low in cooked fats, split into 5 to 6 mini-meals. Clear broth, white rice, steamed fish, and plain yogurt are well tolerated.
8. Is intermittent fasting compatible with a GLP-1?
Possible in the maintenance phase, provided you reach the protein target. Not advised in the escalation phase (weeks 1 to 8).
9. How to manage constipation on Mounjaro?
25 to 30 g of fiber, 2 to 2.5 liters of water, 2 ripe kiwis per day, post-meal walking. Consult beyond 5 days without a bowel movement.
10. Which supplements on GLP-1?
Vitamin D, B12, iron (women), magnesium if needed. Always on medical advice and blood testing.
11. What to do if appetite does not allow reaching the protein target?
Split meals, dense sources (skyr, egg white, protein powder), drink your protein (smoothies, enriched broths).
12. Do you regain weight after stopping GLP-1?
Without a protocol, 68 percent regain within the year. With gradual weaning and maintained habits, this figure drops under 30 percent.
13. How to avoid the hollowed face (Ozempic face)?
Preserve muscle via protein, slow the rate of loss, maintain hydration and dietary collagen.
14. Does Ozempic cause hair loss?
Not directly. The shedding stems from deficiencies in iron, zinc, biotin, and protein linked to rapid loss.
15. How long should you follow this diet?
Throughout the treatment, then at least 12 weeks after stopping. Ideally: make it a lasting nutritional foundation.
Conclusion: turn your treatment into lasting weight loss
A GLP-1 treatment is not a standalone solution. It is a powerful accelerator that only reaches its full potential when combined with a structured eating strategy, active preservation of muscle mass, and vigilance about side effects. Without this foundation, the treatment is expensive for suboptimal results and almost guaranteed weight regain after stopping. With this foundation, it becomes the tool for lasting weight transformation that clinical research promises.
This whole guide boils down to four daily actions: 1.2 to 1.6 g of protein per kilo spread over 4 servings, 2 to 2.5 liters of water outside of meals, strength training 2 to 3 times per week, and intelligent meal splitting on injection days. The rest is putting it into practice.
To turn these principles into a concrete meal plan adapted to your weight, your molecule, your titration phase, and your constraints (halal, kosher, vegetarian, gluten-free, lactose-free), our intake quiz takes three minutes and immediately generates a personalized plan with a shopping list adapted to your usual supermarket. It is free to start.
Download our free "7-Day GLP-1 Meal Plan" PDF (complete recipes, calculated macros, print-ready shopping list).
Generate your personalized plan in 3 minutes (28 days, adapted to your molecule and your food preferences).
Sources and references
- FDA prescribing information for semaglutide (Ozempic, Wegovy), fda.gov
- NICE guidance on Wegovy and Mounjaro, nice.org.uk
- Academy of Nutrition and Dietetics protein recommendations, eatright.org
- NIH obesity and GLP-1 agonists overview, nih.gov
- Wilding JPH et al. (2021), "Once-Weekly Semaglutide in Adults with Overweight or Obesity" (STEP-1), *The New England Journal of Medicine* 384:989-1002
- Jastreboff AM et al. (2022), "Tirzepatide Once Weekly for the Treatment of Obesity" (SURMOUNT-1), *The New England Journal of Medicine* 387:205-216
- Rubino D et al. (2022), "Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance" (STEP-4), *JAMA* 327(2):138-150
- Academy of Nutrition and Dietetics, dietary recommendations for patients on GLP-1 analogs, eatright.org
- NIH, recommendations on lean mass preservation during weight loss, nih.gov