You have been advised to take Orlistat to help you lose weight. This leaflet tells you more about how diet and Orlistat can work together to help you lose weight.
What is Orlistat?
Orlistat is a capsule that can be prescribed by your GP to help you to lose weight. It is also available over the counter at a reduced dose (brand name Alli®). It works in your gut to prevent around one third of the fat you eat from being absorbed. This unabsorbed fat is then passed out of your body through your motions, which means a reduction in energy intake for the body, thereby causing weight loss.
Who can take Orlistat?
Orlistat is a drug licensed for weight loss in the UK.
You must have a BMI of 30kg/m2 or above, or a BMI of 27kg/m2 or above with co-morbidities (such as type 2 diabetes, high blood pressure etc.) and are not contraindicated (see below).
Are there any adverse effects?
If there is excess fat in the foods you eat whilst taking Orlistat, you may experience the following effects:
- Liquid or oily stools
- Oily leakage from the bottom
- Unable to control bowel movements
- Stomachache
If you follow a low-fat diet and the advice given by your doctor or dietitian, you can avoid the treatment effects of Orlistat and lose weight more effectively.
Less common adverse effects:
- Headache
- Respiratory or urinary tract infection
- Hypoglycaemia
- Anxiety
- Gingival and tooth disorders
- Fatigue
- Menstrual disturbances
Hazards and Cautions
Do not take Orlistat
- If you are pregnant or breast-feeding
- If you are taking certain medications such as ciclosporin or blood thinners such as warfarin
- If you are allergic to orlistat or any of the ingredients
- If you have cholestasis (a condition where the flow of bile from the liver is blocked)
- If you have problems absorbing food (chronic malabsorption syndrome)
Talk to your doctor before taking Orlistat:
- If you are taking amiodarone for heart rhythm problems
- If you are taking medicine for diabetes
- If you are taking medicine for epilepsy
- If you have kidney disease
- If you are taking a thyroid medicine (levothyroxine)
- If you are taking medicine for HIV
Medications and supplements
- Due to the mechanism of action of orlistat, take Orlistat 2 hours apart from your medications or supplements to avoid malabsorption
- If you are concerned about the medications you are taking and how they might interact with orlistat, talk to your doctor for further advice
- Orlistat can reduce absorption of some vitamins (e.g. vitamin A, D, E, K), it is essential to have a diet rich in fruit and vegetables
- You may be advised to take a daily multivitamin and mineral supplement (2 hours apart from orlistat) to prevent any deficiencies. If you are concerned, talk to your doctor for further advice
Taking orlistat: Take 1 Orlistat capsule 3 times per day, either with or up to one hour after your meals.
Diet: A reduced fat diet is used alongside Orlistat to help you lose weight. It is important that you do not have more than 15g
of fat intake in any one meal to avoid treatment effects of the drug. You may find it easier if you plan out your meals daily.
Food labelling: The table below will help you identify foods low in fat when you are looking at food labels. Avoid foods which are high in fat, and only have foods which are medium in fat very occasionally.
Fat per 100g
Low - 3g or below
Medium - 5 - 15g
High - More than 15g
The following information guides you on dietary changes for a weight loss diet:
Food: Meat and meat products
Common foods high in fat/energy (to avoid and watch out for)
- Sausages
- Meat with visible fat, e.g steak, lamb or pork chops, streaky bacon
- Skin of poultry
- Pate
- Meat pies/pork pies
Lower fat/energy choices to go for:
- Low fat sausages
- Lean meat/fish
- Reduced fat pate
- Meat without pastry
- Boil/dry oven roast meat/fish
Food: Fat spreads, oils and salad dressings
Common foods high in fat/energy (to avoid and watch out for)
- Butter/lard/ghee/suet/ dripping
- Mayonnaise/cream-based dressing e.g. Thousand Island or Blue Cheese
- Cream based sauces
- Free poured oil used in cooking
- Coconut oil
- Peanut butter (with salt and sugar added)
- Coconut cream/milk
Lower fat/energy choices to go for:
- Lower fat Olive oil-based spread
- Light/extra light mayonnaise or salad cream
- Vinegarette based or fat free salad dressings
- Tomato based sauces
- Spray oil
Food: Cheese and dairy products
Common foods high in fat/energy (to avoid and watch out for)
- Cream
- Creme Fraiche
- Full fat yoghurt
- Full fat milk
- Goat's milk
Lower fat/energy choices to go for:
- Low fat/light cheese spread
- Reduced fat creme fraiche/low fat plain yoghurt instead of cream in dishes
- Reduced fat/light coconut milk
- Diet yoghurt
- Semi skimmed/skimmed/BOB milk
Food: Processed foods
Common foods high in fat/energy (to avoid and watch out for)
- Pastry e.g croissant or sausage rolls
- Deep fried food
- Creamy dips
- Pre-fried frozen products such as chicken nuggets/chicken kiev
Lower fat/energy choices to go for:
- Milk-based dessert made with low fat milk
- Sugar free jelly
- Tomato salsa or tomato-based chutney/relish
- Homemade meals using low fat cooking methods (please see below)
Food: Fruit and Vegetables
(common types that are high in energy/fat to avoid or watch out for)
- Deep fried vegetables e.g. Tempura
- Vegetable crisps
- Tinned vegetables preserved in oil
- Roasted vegetables (in oil)
Lower fat/energy choices to go for:
- Most vegetables are low in energy unless oil/fat is added in cooking
- Include vegetables/ salad as the biggest portion at mealtimes (aim for ½ plate)
- All fresh/frozen/tinned vegetables in water can be included as part of a weight loss diet
Food: Carbohydrates/sugar
Common foods high in fat/energy (to avoid and watch out for)
- Pastry-based snack/desserts
- Potatoes (cooked in oil e.g. deep fried/roasted)
- Pasta in a creamy sauce
- Rice made with cream/creamy sauce e.g. risotto with cream/rice pudding
- High sugar food/snacks e.g. chocolate/cakes
- High sugar drinks e.g. regular soft drinks/fruit juices
- Sugar-based cereal e.g. granola/Frosted cornflakes
Lower fat/energy choices to go for:
- Plain biscuits (no cream/chocolate) and limit to x2
- Rice/pasta cooked in tomato-based sauce
- Potatoes (keep to fist size portion in general) cooked without oil e.g. jacket/ boiled potatoes
- Lower sugar cereal e.g. all bran/no added sugar muesli
- Low sugar drinks e.g. no added sugar fruit squash/water/tea or coffee with no sugar
Cooking methods
Try and avoid:
- Deep fried
- Sauteed
- Roasted with oil
- Shallow fried
Better options are to:
- Grill
- Poach
- Steam
- Microwave
- Air fry dry or with oil spray
- Roasted dry or with oil spray
- Stir fry with 1 teaspoon of oil per person per meal
Sample meal plan
Breakfast:
- 1 slice of whole grain toast with 1 teaspoon of low-fat spread
- 1 boiled egg
- 1 small apple
- Black coffee or tea (no sugar)
Mid-Morning Snack:
- 1 low-fat yogurt
Lunch:
- Grilled chicken salad with mixed greens, cherry tomatoes, cucumber, and a vinaigrette dressing
- 1 small whole grain roll
- Water or no added sugar squash
Afternoon Snack:
- 1 small banana
Dinner:
- Baked salmon with lemon and herbs
- Steamed broccoli and carrots
- 1 small baked potato (no butter)
- Water or herbal tea
Evening Snack:
- 1 small handful of almonds (about 10-12 almonds)
Tips to lose weight
- Use plenty of herbs and spices to flavour food
- Use tomato-based sauces rather than creamy ones for pasta/ rice dishes
- Include vegetables/salad in as many meals as able - fresh/ frozen/canned can all be used
- Plan snacks ahead to be more in control with eating
- Do not go shopping when you are hungry
- Stick to a shopping list or shop online
Drinks
Fluids are vital to keep your body hydrated and for your metabolism to work most effectively. Thirst can often be mistaken for hunger, so when you are hungry try to have a drink first.
Aim for at least 8-10 cups of fluids per day, more when the weather is hot or if you are more active. Go for drinks low in calories such as water, coffee or tea (with no sugar or use sweeteners in hot drinks), no added sugar squash, diet variety of soft drinks or sugar free flavoured water.
Remember - if you are taking your Orlistat medication as prescribed and not experiencing treatment effects, this means that you are having a diet low in fat. This will help you to lose weight. This does not mean that the medication is not working.
What should I do if I get treatment effects?
Experiencing treatment effects means that you are eating too much fat. It is advisable for you to:
- Re-read this leaflet to ensure you are following the advice
- If you are not doing so already, look at food labels closely and opt for low fat foods
- Keep a food and symptom diary - write down everything that you eat for at least a week and note down when you get treatment effects. This should help you to identify foods which are causing the problem
- Contact your dietitian for further advice
What support will I get?
It is essential to keep a food diary whilst you are taking Orlistat. This can help you plan your intake throughout the day.
You can write down any physical activities you may have done as well as thoughts or feelings related to food throughout the
day. This helps to tell you more about your physical activity level and food related emotions. It can also help to identify
which food has caused treatment effects if you suffer from them.
You will be reviewed regularly by your weight management team, who will support you through the weight loss process and monitor your progress in clinic.
What happens if I don't lose weight?
You must lose at least 5% of your start weight in the first 3 months for your prescription to continue. If you do not lose this, the Orlistat treatment is deemed ineffective, and your prescription will be stopped.
Resources
Websites
www.allrecipes.com (look under 'healthy' or 'low fat')
www.nhs.uk/healthier-families/recipes/ (recipes and meal ideas)
Date of Review: February 2025
Date of Next Review: February 2027
Ref No: PI_M_2044 (Salford)