- Protein helps you stay full and protects muscle while you lose weight.
- Many dietitians suggest aiming for more than the standard UK reference intake when losing weight — often around 1.2–1.6 g per kg of body weight a day — unless you have kidney disease.
- Aim for 30 g of fibre a day and plenty of fluids.
- Everyone in the UK is advised to consider a vitamin D supplement in autumn and winter.
Why protein matters
When you eat less, the body can break down muscle as well as fat. Eating enough protein — together with strength training — helps you keep muscle, which keeps you strong and supports your metabolism. Protein is also the most filling nutrient, so it makes a calorie deficit easier to live with.
How much protein?
The UK reference intake is 0.75 g per kilogram of body weight a day, but during weight loss many experts suggest aiming higher, often around 1.2–1.6 g/kg. If you have kidney disease, check with your GP first. A practical approach is 25–30 g at each main meal:
| Food | Approximate protein |
|---|---|
| Chicken breast, 120 g cooked | 35 g |
| Salmon fillet, 120 g | 25 g |
| Greek yoghurt, 200 g | 20 g |
| Lentils, 200 g cooked | 18 g |
| Tofu, 150 g | 18 g |
| Two large eggs | 13 g |
Building a filling plate
- Half vegetables or salad
- A quarter protein: fish, poultry, eggs, beans, lentils, tofu or lean meat
- A quarter high-fibre carbohydrates: wholegrain bread, oats, brown rice, potatoes with skins
- A small amount of healthy fat, such as olive oil, nuts or avocado
Fibre and fluids
UK guidance recommends 30 g of fibre a day — most adults eat far less. Fibre from vegetables, fruit, beans, oats and wholegrains keeps you full and supports digestion. Drink 6–8 glasses of fluid a day, more in hot weather or when active; water, milk and sugar-free drinks all count.
When you are eating much less
If your appetite is low — for example while on a medical weight-loss programme — prioritise protein first at each meal, choose smaller and more frequent meals, and avoid long gaps without fluids. Consider a vitamin D supplement (10 micrograms a day) in autumn and winter, as advised for everyone in the UK. If you follow a vegan diet, make sure you get vitamin B12.
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Start the free assessmentFrequently asked questions
Do I need protein shakes?
Not usually. Food is the best source, but a shake can be a convenient way to reach your protein target if your appetite is low.
Should I cut out carbohydrates?
You don’t have to. Choosing high-fibre carbohydrates in sensible portions works well for most people. What matters most is a diet you can keep up.
Is fruit too sugary when I’m trying to lose weight?
Whole fruit is filling and full of fibre and nutrients. Fruit juice and smoothies are easier to over-consume, so keep those to a small glass a day.
This page is general health information. It does not replace advice from your GP or another healthcare professional who knows your history. If you have symptoms that worry you, contact your GP or NHS 111; in an emergency call 999. Prescription treatment is only supplied after an assessment by a registered prescriber.