How much fat should I actually eat?

The label gives a target and a table. It asks for a nutritionally balanced, reduced-calorie diet containing approximately 30% of calories from fat, distributed over three main meals, and the patient information translates that into grams: about 50 g of fat on a 1,500-calorie day, 53 g at 1,600, 60 g at 1,800 and 67 g at 2,000.

Do I take a capsule with every meal?

Only with meals that contain fat. The label says to take one capsule with each main meal containing fat, during the meal or up to one hour after it, and that if a meal is occasionally missed or contains no fat, the dose can be omitted.

Why do I need a multivitamin?

Because orlistat reduces the absorption of some fat-soluble vitamins and beta-carotene. The Xenical label says patients should be strongly encouraged to take a multivitamin containing fat-soluble vitamins once a day, at least 2 hours before or after orlistat, such as at bedtime. The Alli label says the same, more briefly: take a multivitamin once a day, at bedtime.

Should I start the diet before the capsules?

The Alli label suggests exactly that. Under "When using this product" it says to follow a well-balanced, reduced-calorie, low-fat diet, and to try starting that diet before taking orlistat. It also says diet and exercise are the starting points for any weight loss programme and to try those first.

Does alcohol affect how orlistat works?

The label makes one specific statement here: ethanol does not affect the effect of orlistat on preventing the absorption of fat. Alcohol is not otherwise listed in the orlistat interactions section, so we will not add a rule the label does not contain.

What to eat on orlistat

Q: What happens if I eat a really fatty meal?

The label says the possibility of gastrointestinal effects increases. The Alli label lists what those look like: gas with oily spotting, loose stools, and more frequent stools that may be hard to control. It also says eating a low-fat diet lowers the chance of those bowel changes.

What the label asks for

Approximately 30% of calories from fat

The Xenical label states it as a dosing instruction rather than lifestyle advice: the patient should be on a nutritionally balanced, reduced-calorie diet that contains approximately 30% of calories from fat, and the daily intake of fat, carbohydrate and protein should be distributed over three main meals. The Alli Drug Facts label says the same thing in shorter form — follow a well-balanced, reduced-calorie, low-fat diet, and try starting that diet before taking orlistat. Both add a daily multivitamin, taken away from your dose.

What to prioritise

When your appetite is 50% of what it used to be, every bite has to earn its place. Here is the priority stack.

Fat

~30% of calories, spread out

The label gives a worked table of what 30% looks like in grams, and warns that taking orlistat with a single very fatty meal increases the chance of gastrointestinal effects.

The label fat table

1,500 calories a day: about 50 g of fat
1,600 calories a day: about 53 g of fat
1,800 calories a day: about 60 g of fat
2,000 calories a day: about 67 g of fat
Spread that across three main meals, not one

A daily multivitamin

At least 2 hours apart

Orlistat reduces the absorption of some fat-soluble vitamins and beta-carotene, so both labels ask for a supplement — and both say to take it away from your dose.

What the label says

A multivitamin containing vitamins A, D, E, K and beta-carotene
Once a day, at least 2 hours before or after orlistat
Bedtime is the timing both labels suggest
Alli: take a multivitamin once a day, at bedtime

Habits that help vs habits that hurt

These patterns come up repeatedly in clinical guidance and community experience.

Prioritise these

Aim for approximately 30% of calories from fat, as the label describes
Spread fat, carbohydrate and protein across three main meals
Take a capsule with each main meal that contains fat
Skip the dose when a meal is missed or has no fat in it
Take a daily multivitamin with fat-soluble vitamins, at least 2 hours apart
The Alli label suggests starting the diet before you add the capsules

Watch out for

Take orlistat with a single very high-fat meal — the label says GI effects increase
Eat a diet with more than 30% of total daily calories from fat
Load your day fat into one big meal instead of spreading it over three
Take your multivitamin at the same time as a capsule
Take more than 3 capsules in a day (Alli) or more than 120 mg three times a day (Xenical)
Skip the diet and rely on the capsules — the label describes them as working together

The high-fat meal trap

The bowel side effects track how much fat is in your meal

The Alli label explains the mechanism in plain language and then draws the practical conclusion. It says orlistat works by preventing the absorption of some of the fat you eat, that the fat passes out of your body, and that you may therefore get gas with oily spotting, loose stools, and more frequent stools that may be hard to control — followed immediately by the line that matters: eating a low-fat diet lowers the chance of having these bowel changes. The prescription label makes the same point clinically, saying gastrointestinal events may increase when orlistat is taken with a diet high in fat, meaning more than 30% of total daily calories, and that if orlistat is taken with any one meal very high in fat, the possibility of gastrointestinal effects increases. This is the rare case where the side effects are directly under your control.

Sample meal ideas

These are not prescriptions — they are starting points. Adapt to your preferences, culture, and dietary needs.

Breakfast

Porridge with fruit
Wholegrain toast with a thin spread
Plain yogurt with berries

If a breakfast genuinely has no fat in it, the label says the dose can be omitted.

Lunch

A sandwich with lean filling and salad
Vegetable or lentil soup with bread
A rice or grain bowl with beans

The label asks for fat to be distributed across three main meals rather than loaded into one.

Dinner

Grilled fish or chicken with vegetables and potatoes
A tomato-based pasta dish
A bean chilli with rice

Rich, creamy or fried dinners are exactly where the label says gastrointestinal effects increase.

Bedtime

Your daily multivitamin

Both labels put the multivitamin at bedtime, at least 2 hours away from a dose of orlistat.

Common questions

Written and maintained by one person · Built with agentic AI tools · Every number checked against the cited trial · Not medical advice

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Last reviewed: September 2026

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