How Much Protein Do You Need When Dieting?

Why Protein Is So Important When Dieting

Three mechanisms make protein uniquely valuable during a calorie deficit. First, muscle preservation: in a calorie deficit, your body can use both fat and muscle tissue for energy. High protein intake signals the body to preserve muscle, directing fat to be broken down preferentially. Second, satiety: protein is the most filling macronutrient — it suppresses the hunger hormones ghrelin more effectively than carbohydrates or fat, making it easier to eat less without feeling deprived. Third, the thermic effect: your body burns 25–30% of protein calories just digesting it, compared to 6–8% for carbohydrates and 2–3% for fat. This effectively means dietary protein has fewer usable calories than its label suggests.

The Research-Backed Protein Targets

Current evidence supports a protein intake of 1.6–2.2 g per kilogram of bodyweight per day for people dieting while trying to preserve muscle mass. The higher end of this range (2.0–2.4 g/kg) is most relevant for people who do resistance training — lifting weights or performing bodyweight exercises regularly — as they have a greater stimulus for muscle protein synthesis.

For a 70 kg woman dieting at 1,800 calories per day: 1.6 g/kg = 112 g protein per day (minimum); 2.2 g/kg = 154 g protein per day (optimal). For a 90 kg man dieting at 2,200 calories per day: 1.6 g/kg = 144 g protein; 2.2 g/kg = 198 g protein. These ranges may seem high if you are used to general health recommendations (which are lower), but they are specifically designed for body recomposition — not just survival.

Is It Possible to Eat Too Much Protein?

For healthy adults without pre-existing kidney disease, the evidence does not support concerns about high protein intake causing harm. Studies in healthy adults consuming up to 3.4 g/kg per day found no adverse kidney, bone, or liver effects. The practical concern is that very high protein intakes leave less room for carbohydrates and fats, which can make the diet less enjoyable and harder to sustain.

A sensible upper target is 2.2–2.4 g per kilogram of bodyweight. Above this level, additional protein provides minimal additional muscle preservation benefit and simply displaces other foods without adding value.

How to Hit Your Protein Target: UK Food Examples

A practical daily structure for a 70 kg woman targeting 140 g protein at 1,800 kcal:

• Breakfast: 200 g 0% Greek yogurt + 50 g oats + 100 ml skimmed milk = ~25 g protein, ~320 kcal.
• Lunch: 1 tin tuna in spring water + large salad + 1 tbsp olive oil = ~28 g protein, ~320 kcal.
• Dinner: 180 g grilled chicken breast + 80 g brown rice (dry weight) + 150 g broccoli = ~60 g protein, ~580 kcal.
• Snack: 200 g cottage cheese + cherry tomatoes = ~24 g protein, ~190 kcal.
• Total: ~137 g protein, ~1,410 kcal — leaving 390 kcal for additional carbs, fats, or a second snack.
• Adding 2 boiled eggs at any point adds 13 g protein for ~160 kcal — a simple way to bridge any remaining gap.

Protein Timing: Does It Matter?

Research suggests that distributing protein across meals (rather than eating most of it in one sitting) optimises muscle protein synthesis. Aim for 30–50 g of protein per meal across 3–4 eating occasions. There is good evidence for a protein-rich meal within two hours of resistance training to maximise muscle retention.

The anabolic window (the idea that you must eat protein immediately post-workout or lose all gains) is largely overstated. What matters most is total daily protein intake — not timing. If you eat enough protein across the day, the exact timing is a minor detail.

The Best Protein Sources for Dieting in the UK

The most effective protein sources for dieting share two qualities: they are high in protein relative to calories, and they are filling. The best choices available in UK supermarkets include chicken breast (31 g protein per 100 g, ~165 kcal), tinned tuna in spring water (25 g per 100 g, ~100 kcal), 0% Greek yogurt (10 g per 100 g, ~57 kcal), cottage cheese (12 g per 100 g, ~80 kcal), egg whites (11 g per 100 g, ~50 kcal), and cooked prawns (20 g per 100 g, ~90 kcal).

Use our free meal plan generator to create a complete high-protein week with calculated protein per meal. You can specify your supermarket, calorie target, and the generator automatically distributes protein across all meals.