Short answer: Orlistat is taken with a reduced-calorie, lower-fat diet. Eat a balanced diet with slightly fewer calories, rich in fruit and vegetables, with about 30% of your calories from fat. Spread your fat, carbohydrate and protein over three main meals. On a 2,000 kcal day, that means up to about 67g of fat (Xenical SmPC, section 4.4; alli SmPC, section 4.2), shared across your three main meals. Avoid high-fat foods such as processed or fatty meats, fried food, biscuits and cakes (NHS website), and fatty snacks between meals (Xenical leaflet, section 3). Side effects in the gut are more likely after a meal high in fat. You still need to eat some fat (NHS website), because orlistat only works on the fat in the meal you take it with (Xenical leaflet, section 3). Take a daily multivitamin containing vitamin D, at least 2 hours after a dose of orlistat, or at bedtime.
This guide sets out what the UK product information for orlistat 120mg (Xenical) and orlistat 60mg (alli) and the NHS say about food, as of October 2026: what to eat, how much fat a day and a meal, foods to avoid, reading food labels, alcohol, keto, vitamins, and a week of meal ideas. It is general guidance, not a personal calorie target: our pharmacist can talk your diet through with you.
What should you eat on orlistat?
Eat a balanced diet with slightly fewer calories, rich in fruit and vegetables, with about 30% of your calories from fat. Spread your fat, carbohydrate and protein over three main meals. That is the diet our pharmacist works to. The NHS describes it as a healthy, calorie-controlled diet with plenty of fruit and vegetables, and adds: "You'll also need to eat some fat". The alli leaflet advises starting the diet before you begin treatment (section 2), so the change of eating comes first and the capsule second.
How much fat can you eat on orlistat?
About 30% of your calories, which on a 2,000 kcal day means up to about 67g of fat (Xenical SmPC, section 4.4; alli SmPC, section 4.2), shared across your three main meals. The Xenical product information counts more than that as a diet high in fat, with which side effects in the gut may increase (section 4.4).
- Calories from fat30%
About 30% of your calories from fat, spread over three main meals (Xenical SmPC, section 4.2).
- Fat on a 2,000 kcal day67g
On a 2,000 kcal day, 30% of calories from fat is about 67g of fat (Xenical SmPC, section 4.4).
The same rule at other daily calorie levels, as general figures:
| Daily calories | Fat a day (about 30%) | Fat per main meal (a third) |
|---|---|---|
| 1,200 kcal | About 40g | About 13g |
| 1,400 kcal | About 47g | About 16g |
| 1,600 kcal | About 53g | About 18g |
| 1,800 kcal | About 60g | About 20g |
| 2,000 kcal | About 67g | About 22g |
The 2,000 kcal row is the product information's own figure; the others use the same sum (30% of calories, at 9 kcal in a gram of fat). They are general figures, not a personal target. A meal much higher in fat than your others makes the side effects in the gut more likely: "If orlistat is taken with a meal very high in fat, the possibility of gastrointestinal adverse reactions may increase" (Xenical SmPC, section 4.4).
What foods should you avoid on orlistat?
High-fat foods, such as processed or fatty meats, fried food, biscuits and cakes (NHS website), and fatty snacks between meals, such as biscuits, chocolate and savoury snacks: the Xenical leaflet says "to gain optimal benefit, avoid the intake of food containing fat between meals" (section 3).
| Choose more often | Have less often |
|---|---|
| Fruit and vegetables | Processed or fatty meats |
| Lean meat with the visible fat cut off, skinless chicken, white fish | Fried food |
| Beans, lentils and other pulses | Biscuits and cakes |
| Skimmed or semi-skimmed milk, plain low-fat yoghurt | Chocolate and savoury snacks between meals |
| Wholegrain bread, rice, pasta and potatoes | Full-fat versions where a lower-fat one exists |
| Food that is grilled, baked, steamed or boiled | Food cooked in a lot of oil or butter |
How do you read food labels on orlistat?
Check the fat per 100g: for food, more than 17.5g of fat is high, and 3g or less is low (NHS website, how to read food labels; drinks use different figures). Some packs also colour the fat red, amber or green on the front: red means high, amber medium and green low.
| Per 100g of food | High | Low |
|---|---|---|
| Fat | More than 17.5g | 3g or less |
| Saturated fat | More than 5g | 1.5g or less |
A food high in fat is not banned: the NHS advice is to have such foods less often and in small amounts, and their fat counts towards the meal's share.
What happens if you eat a fatty meal on orlistat?
The side effects in the gut, such as oily stools and needing the toilet urgently, become more likely. Side effects in the gut are more likely after a meal high in fat. Do not take an extra capsule: "If you eat a high-fat meal, do not take more than the recommended dose" (alli leaflet, section 2). What to expect, and what helps, is in orlistat side effects.
Do you take orlistat with every meal, and what if a meal has no fat?
Take one capsule immediately before, during, or up to one hour after each main meal, up to three times a day. If you miss a meal, or a meal contains no fat, skip that dose. The full timing rules, including missed capsules, are in how to take orlistat.
Can you drink alcohol on orlistat?
The UK product information reports no interaction between orlistat and alcohol in interaction studies (Xenical SmPC, section 4.5). Alcoholic drinks still count towards the calories in your reduced-calorie diet, and drinks made with cream are high in fat, so they count towards the fat too.
Thinking about orlistat? Our consultation asks about your health, your weight and the medicines you take, and a GPhC-registered pharmacist reviews your consultation before anything is supplied.
Start your orlistat consultationCan you do keto on orlistat?
No. A very high-fat diet such as keto does not fit with orlistat: the product information asks for about 30% of calories from fat (Xenical SmPC, section 4.2), and says side effects in the gut may increase with a diet high in fat (alli SmPC, section 4.4).
What does a 7-day orlistat meal plan look like?
Three balanced main meals a day with some fat in each, and no fatty snacks between them: there is no set orlistat menu, so the week below is lower-fat meal ideas built on those rules, not a prescription. Swap meals around to suit you.
| Day | Breakfast | Lunch | Evening meal |
|---|---|---|---|
| Monday | Porridge made with semi-skimmed milk, with berries | Wholemeal pitta with grilled chicken breast and salad | Grilled white fish, new potatoes and green vegetables |
| Tuesday | Wholegrain cereal with semi-skimmed milk and a banana | Lentil and vegetable soup with a wholemeal roll | Turkey mince chilli with kidney beans and rice |
| Wednesday | Plain low-fat yoghurt with fruit and a sprinkle of seeds | Jacket potato with baked beans and salad | Chicken and vegetable stir-fry cooked in a little oil, with noodles |
| Thursday | Wholemeal toast with a thin scrape of spread and sliced tomatoes | Tuna (in spring water) salad sandwich on wholemeal bread with a low-fat dressing | Chickpea and vegetable curry cooked in a little oil, with rice |
| Friday | Porridge made with semi-skimmed milk, with grated apple and cinnamon | Leftover chickpea curry with a wholemeal wrap | Skinless chicken with roasted vegetables (a teaspoon of oil) and couscous |
| Saturday | A boiled egg with wholemeal toast | Homemade vegetable soup with crusty bread | Lean beef and vegetable stew with potatoes |
| Sunday | Plain low-fat yoghurt with fruit and a few chopped nuts | Roast chicken without the skin, boiled potatoes and vegetables | Wholemeal pasta with a tomato, lentil and vegetable sauce made with a little oil |
Each meal has some fat, which orlistat needs to act on; take your capsule with it.
Do you need vitamins on orlistat?
Yes, a daily multivitamin. Orlistat reduces how much of the fat-soluble vitamins A, D, E and K you absorb from food. Take a daily multivitamin containing vitamin D, at least 2 hours after a dose of orlistat, or at bedtime. The alli leaflet says the multivitamin should contain vitamins A, D, E and K (section 2). Any plain multivitamin that does is fine.
Should you keep to the diet after you stop orlistat?
Yes. The alli product information says the diet and exercise programme should carry on after you stop (alli SmPC, section 4.2), and the NHS advises carrying on with a balanced diet and exercise.
Orlistat works alongside a low-fat, calorie-controlled diet and increased physical activity. Any weight lost during treatment is likely to return if these lifestyle changes are not maintained after stopping the medication.
How orlistat works on the fat in your meals is in how does orlistat work, and how it compares with the GLP-1 medicines in orlistat vs Mounjaro and Wegovy. The other licensed options are on our weight loss page, and you can check your BMI with our BMI calculator.