How to get the best results from Orlistat

Dr Kathryn Basford

Medically reviewed by

Dr Kathryn Basford

Last reviewed: 26 Apr 2022

Orlistat is a medicine you can take to help you lose weight. You will need to have made changes to your diet and increased your levels of exercise before you start taking Orlistat. Although making these lifestyle changes and sticking to them can be a challenge, having support from family and friends can be helpful. You can also speak to your doctor or another healthcare professional for advice.

If you’re thinking about taking Orlistat, this guide will help you with how you can get the best results from it. If you are taking Orlistat and you feel that it is not working (you are not losing weight on Orlistat), we’ll recommend some things you can try.


To get the best results from Orlistat, it’s important to:

  • eat a healthy, balanced diet daily
  • avoid eating too much fat each day
  • get plenty of exercise, even a short daily walk
  • make sure you are taking Orlistat correctly, with meal times
  • consider taking a vitamin supplement, that includes vitamins A, D, E and K

Make sure you are taking the right dose of Orlistat. Take 1 Orlistat capsule 3 times a day with a drink of water and with your meals – either just before, during or no later than 1 hour after eating a meal. If you skip a meal, or eat a meal that does not contain any fat, you should not take a dose of Orlistat.

Try and take regular measurements so you can monitor if Orlistat is working, and consider weighing yourself once a week. It can also be helpful to measure around your waist and thigh. Keep a note of these measurements so you can see how they change over time.

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What does Orlistat do?

Orlistat is a medicine to help with weight loss, in addition to lifestyle changes including a healthy diet and plenty of exercise. You can buy Orlistat as the generic version or as the branded version called Xenical.

If you have a high BMI (Body Mass Index), your doctor or pharmacist may have recommended you take Orlistat to help you lose weight.

You can take Orlistat if your BMI is:

  • 30 or above
  • 28 or above and you have certain conditions, such as type 2 diabetes or high blood pressure

Orlistat works by reducing the amount of fat absorbed from the food you eat. In your digestive system, fats are broken down by enzymes such as lipases. Orlistat inhibits lipases, which means it blocks the normal action of lipases.

So when you take Orlistat, less fat is broken down (digested) which means that less fat is absorbed by your body. Instead of absorbing these fats, your body will pass them out when you go to the toilet. Orlistat reduces the amount of fat you absorb from the food you eat by about 30%.

What to eat when taking Orlistat to get the best results

When taking Orlistat, it’s important to eat a healthy, balanced diet to get the best results. You’ll also need to eat a low fat diet, so you should aim to get no more than 30% of your daily calories from fat. You can do this by making sure you eat plenty of fruit and vegetables, and by avoiding eating too many food items that are high in fat. Try and make sure that the amount of fat, carbohydrate and protein you eat is spread over your 3 meals a day.

As well as reducing the amount of fat you absorb from your food, Orlistat can also reduce the amount of fat soluble vitamins you absorb. These vitamins need fat to be absorbed into your body, so we recommend you take a vitamin supplement to make sure you are still getting enough vitamins A, D, E and K. Take these vitamins at least 2 hours after taking Orlistat, ideally at bedtime.

What foods to avoid when taking Orlistat

Try to avoid eating foods with a very high fat content when taking Orlistat. If you eat a meal with a high fat content whilst taking Orlistat, you may be more likely to experience side effects such as:

  • pain or discomfort in your tummy (abdomen)
  • needing to go to the toilet more often or diarrhoea
  • wind
  • oily discharge
  • oily or fatty poo (stools)

By reducing your daily fat intake, you can reduce the risk of side effects from Orlistat.

You can use the nutrition labels on food to help spot foods that might be high in fat. Aim to avoid or limit foods that contain more than 5g of fat per 100g. Examples of very high fat foods include butter, cheese, fried food, fatty meats, chocolate and cakes. There may be alternative foods you can swap a high fat food for, for example, try swapping:

  • butter for a low fat spread
  • full fat milk for skimmed or semi skimmed milk
  • full fat cheese for cottage cheese
  • chips and roast potatoes for mash or boiled potatoes
  • avocados for other green vegetables such as lettuce or cucumber
  • fried food for steamed or boiled food
  • chocolate, sweets and cakes for crispbreads or rice cakes

The NHS has a free food scanner app available which can help you find healthier foods you can swap to.

How much should I be eating when I’m taking Orlistat?

When taking Orlistat, you’ll need to consider how much you are eating. The NHS recommends that adult men should eat no more than 2,500 calories per day and adult women no more than 2,000 calories per day. To lose weight, your doctor may recommend that you eat less than this when taking Orlistat. An Asda Online Doctor can also provide advice on how much to eat based on your needs.

There are lots of resources available to help you with how much and what to eat. You may find it helpful to think ahead and plan your meals for the day or for the week. You can use the nutrition labels on foods to check the calorie content. You can also check the calorie content of different foods using the NHS calorie checker.

You can only start taking Orlistat if you have already made changes to your lifestyle to help you lose weight. This means reducing your calorie intake and increasing your amount of exercise. Once you have lost weight, you will need to keep these changes in place to make sure that you keep it off for good.

What happens if I eat too much when taking Orlistat?

If you eat too much when taking Orlistat, you may not lose weight. Orlistat reduces the amount of fat that you absorb from the food you eat. This does not mean that if you eat extra fat the effects of the extra eating will be cancelled out by Orlistat. To lose weight, you will need to reduce the amount you eat and increase your levels of exercise, as well as taking Orlistat.

If you eat a lot of fatty food whilst taking Orlistat, you may be more likely to experience side effects.

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Can I snack while taking Orlistat?

You can still have snacks whilst taking Orlistat, but snacking is unlikely to help you lose weight if it takes you over your planned calorie intake for the day. It is recommended to eat 3 meals a day and small healthy snacks if needed. Cutting out snacks can be a helpful way to try and lose weight as it will reduce your overall calorie intake for the day, as long as meal sizes are kept the same.

You can take 1 Orlistat up to 3 times a day, with your main meals. Most people taking Orlistat take it at breakfast, lunch and dinner. If you have snacks as well as these 3 meals, you won’t be able to take an extra dose of Orlistat.

If you do have snacks when you are taking Orlistat, try and avoid foods with a high fat content, for example biscuits or chocolates. If you have extra snacks between meals, Orlistat will not be able to reduce the fat absorbed from these snacks.

Medically reviewed by:
Dr Kathryn Basford

Dr Kathryn Basford is a qualified GP who works as a GP in London, as well as with ZAVA. She graduated from the University of Manchester and completed her GP training through Whipps Cross Hospital in London.

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Article created: 26 Apr 2022

Last reviewed: 26 Apr 2022

(Reviews are for ZAVA UK)

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