How Orlistat Works and Why Diet Matters

No weight loss journey is truly complete without the right diet plan. Even alongside medications, long-term success depends on sustainable lifestyle changes.

One such treatment is Orlistat, which works by blocking about a third of dietary fat absorption. Taken three times daily with meals, Orlistat requires a low-fat diet, not exceeding 15g of fat per meal to minimise side effects and work effectively. This is a clear example where diet can directly affect treatment outcomes.

Read on for a sample diet plan which can help get the most out of your Orlistat treatment.

The Golden Rule: 15g of Fat Per Meal

Health experts advise when taking Orlistat, fat intake should not exceed 15g per meal. Lets break that down:

  • Daily fat intake of approximately 40 to 50g - split into 15g per meal - roughly one tablespoon of olive oil

  • The 30% rule - no more than 30% of the day's calories should come from fat. Based on a 1,400 to 1,500 calorie diet - this aligns with 40-50g fat daily.

  • Check the labels - foods showing no more than 5g fat per 100mg are generally defined as ‘low-fat’

7-Day Orlistat Meal Plan

The following Orlistat meal plan provides 7 days of low-fat meals. Each meal contains under 15g fat with a daily calorie target of approximately 1,400 to 1,500 kcal. On average:

  • 1 gram of fat provides 9 calories
  • 1 gram of carbohydrates contains 4 calories
  • 1 gram of protein contains 4 calories

Using this information along with nutritional information on food packets can help formulate a diet plan such as the sample plan below:

Day 1

Meal Food Choice Fat (g) Calories
Breakfast 40g porridge with 200ml skimmed milk and a handful of blueberries 3g 280 kcal
Lunch Tuna salad wholemeal wrap (tuna in brine) with 1 tsp light mayo and spinach 5g 320 kcal
Dinner Grilled skinless chicken breast with 150g boiled new potatoes and steamed broccoli 4g 410 kcal
Snack 1 apple and a low-fat probiotic yoghurt 1g 140 kcal
TOTAL 13g 1,150 kcal

Day 2

Meal Food Choice Fat (g) Calories
Breakfast 2 slices wholemeal toast with 2 tbsp low-fat cottage cheese and sliced tomatoes 4g 290 kcal
Lunch Roasted tomato and basil soup with a small wholemeal roll 5g 310 kcal
Dinner Turkey mince bolognese (lean) with 60g wholewheat spaghetti 7g 480 kcal
Snack 2 large rice cakes with a thin layer of honey 1g 120 kcal
TOTAL 17g 1,200 kcal

Day 3

Meal Food Choice Fat (g) Calories
Breakfast 1 poached egg on 1 slice of unbuttered sourdough toast 6g 240 kcal
Lunch Prawn stir-fry with ginger, garlic, soy sauce and 150g rice noodles 3g 340 kcal
Dinner Baked cod fillet with lemon & parsley, served with mashed peas and carrots 4g 390 kcal
Snack 100g fat-free Greek yoghurt with honey 0g 110 kcal
TOTAL 13g 1,080 kcal

Day 4

Meal Food Choice Fat (g) Calories
Breakfast 45g Bran flakes with semi-skimmed milk and a sliced banana 4g 310 kcal
Lunch Sliced turkey breast in pitta bread with grated carrot, cucumber and 1tsp mustard 3g 300 kcal
Dinner Sweet potato and chickpea curry with 50g brown rice 6g 450 kcal
Snack Small bag of plain popcorn 2g 90 kcal
TOTAL 15g 1,150 kcal

Day 5

Meal Food Choice Fat (g) Calories
Breakfast Smoothie: 1 scoop whey protein, 100g frozen berries with water or skimmed milk 2g 250 kcal
Lunch Jacket potato with baked beans and large salad (no dressing) 1g 380 kcal
Dinner Grilled lean beef steak, with a baked sweet potato and asparagus 9g 420 kcal
Snack 4 wholegrain crackers with low-fat light soft cheese 4g 180 kcal
TOTAL 16g 1,230 kcal

Day 6

Meal Food Choice Fat (g) Calories
Breakfast Mushroom (2-egg) omelette cooked with low-fat cooking spray 10g 260 kcal
Lunch Couscous salad with grilled peppers, chickpeas, parsley and lemon juice 4g 350 kcal
Dinner 100g grilled Salmon fillet with steamed kale and 2-3 new potatoes 13g 440 kcal
Snack 2 satsumas or a peach 0g 60 kcal
TOTAL 27g 1,110 kcal

Day 7

Meal Food Choice Fat (g) Calories
Breakfast Low sugar granola with fat-free natural yoghurt 6g 320 kcal
Lunch Lean ham and mustard sandwich on wholemeal bread 5g 290 kcal
Dinner Vegetable and lentil stew with a small plain chapatti or wholemeal pitta 7g 460 kcal
Snack 1 small square of 70% cocoa dark chocolate 4g 80 kcal
TOTAL 22g 1,150 kcal

Foods to Avoid on Orlistat

Orlistat users should avoid consuming high-fat foods as these can affect weight loss and cause GI side effects, such as oily stools, flatulence with discharge and liquid stools.

As a guideline, whilst on treatment, it's best to stick to foods containing less than 5g of fat per 100g. These foods are considered low-fat and are less likely to cause side effects.

Common foods high in fat can be swapped for a low-fat alternative, as outlined below:

Type Food Low-fat alternative
Meat Visible fat on meat, skin on, fatty meat (sausages, black pudding) Lean meats or pulses(lentils & beans)
Fish Oily fish, fish canned in oil, fried or battered fish White fish (cod, plaice)
Eggs Fried eggs, scotch eggs Egg whites, boiled/poached egg
Dairy Whole milk, cream, ice cream, evaporated milk Skimmed milk, semi-skimmed milk, low fat oat/soya/coconut milk
Cheese Full fat cheese, cream cheese Cottage cheese, low fat cheese spreads
Fat Lard, dripping, vegetable oils, butter/margarine, all fried foods Spray oils, low fat spread
Cereals Pastries, biscuits/cakes, dumplings, fried bread Wholemeal bread, brown rice, low-fat /sugar breakfast cereals
Beverages Full fat milk drinks, instant malt drinks Tea/coffee, fruit juices, low fat milk drinks (made with skimmed or semi-skimmed milk)

Vitamins and Supplements on Orlistat

Orlistat reduces the absorption of fat-soluble vitamins: A, D, E and K. These vitamins need fat to be transported through the body. To avoid a deficiency, patients should take a daily multivitamin containing these vitamins, leaving a 2 hour gap between these and Orlistat

Some medicines also rely on fat to be absorbed. These should also be spaced 2 hours apart from orlistat to avoid absorption issues.

Orlistat Shopping List

To ensure your kitchen is ‘Orlistat-friendly’, save the below Orlistat shopping list which includes low-fat UK supermarket staples:

Fruit and vegetables

  • Leafy greens - spinach, kale and rocket

  • Berries - blueberries, raspberries, strawberries

  • Crunchy vegetables - carrots, peppers, cucumber, broccoli

  • Potatoes - new potatoes and sweet potatoes

  • Fruits - bananas, apples

Proteins & Dairy

  • Skinless chicken breast and extra-lean turkey mince

  • White fish - cod, haddock, plaice

  • Tinned tuna - in brine (not oil)

  • Eggs

  • Low fat cottage cheese

  • Skimmed or semi-skilled milk

  • Fat-free greek or natural yoghurt

Carbohydrates

  • Wholemeal bread, wraps or pitta bread

  • Oats and bran flakes

  • Wholewheat pasta and brown rice

  • Low-fat cooking spray

  • Tinned tomatoes

  • Tinned chickpeas/lentils

  • Light mayo

FAQs

What vitamins should you take with orlistat?

Take a daily multivitamin containing vitamins A, D, E, K, and beta-carotene, as orlistat reduces absorption of these fat-soluble vitamins. Take the multivitamin at least two hours apart from your orlistat dose, ideally at bedtime.

Can you drink alcohol on orlistat?

Yes, you can drink alcohol while taking orlistat, but it may slow weight loss and add empty calories. Alcohol does not interact directly with orlistat. Choose low-calorie options and drink in moderation. Be aware that some alcoholic drinks are high in hidden sugars.

What can you not eat on orlistat?

Avoid foods high in fat, including fried foods, full-fat dairy, fatty meats, creamy sauces, and processed snacks like crisps and pastries. Check food labels and choose options with less than 5 grams of fat per 100 grams. High-fat meals cause unpleasant GI side effects while on orlistat.

How much fat can you eat on orlistat?

Each meal should contain no more than 15 grams of fat, with a total daily intake of around 40 to 50 grams. Fat should account for approximately 30% of your daily calories. Distribute your fat intake evenly across three main meals rather than saving it for one.

Do you take orlistat with every meal?

Take orlistat three times a day with each main meal that contains fat. Take it immediately before, during, or up to one hour after eating. If you skip a meal or eat a meal with no fat, you can skip that dose. Do not double up on missed doses.

What happens if you eat too much fat on orlistat?

Eating meals high in fat while taking orlistat will likely cause gastrointestinal side effects including oily stools, flatulence with discharge, and an urgent need to go to the toilet. These effects are temporary and resolve when you return to a low-fat diet.


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