Cutting Phase Diet UK: Lose Fat While Keeping Your Muscle

The Cutting Phase: Goals and Timeline

A cutting phase typically follows a period of muscle building (a "bulk") and aims to reduce body fat percentage while retaining lean mass. The target rate of fat loss during a cut is 0.5–1% of body weight per week — fast enough to make meaningful progress without losing significant muscle.

For a 90 kg person carrying 20% body fat, a 10-week cut at 0.5 kg per week would lose approximately 5 kg of fat (assuming muscle is well-preserved) — dropping to around 15% body fat. Most people find a cut of 8–16 weeks effective before diet fatigue sets in and a maintenance phase is needed.

Setting Up Your Cutting Calories

A cutting deficit of 500–700 calories per day below TDEE is appropriate for most people. This produces fat loss of 0.5–0.7 kg per week. Larger deficits (750+ calories below TDEE) accelerate fat loss but substantially increase muscle loss risk and hunger, making the cut harder to sustain.

For a moderately active 85 kg man with a TDEE of 2,700 kcal, a cutting target of 2,000–2,200 kcal per day creates a meaningful 500–700 calorie deficit. For a moderately active 65 kg woman with a TDEE of 2,000 kcal, a cutting target of 1,400–1,500 kcal creates the same deficit.

Protein: The Most Important Cutting Variable

Protein intake during a cut should be higher than during maintenance or building — not lower. The research supports 2.0–2.4 g of protein per kg of body weight during a calorie deficit to maximise muscle retention. For an 85 kg man, that means 170–200 g of protein per day.

This high protein intake serves two purposes: it signals the body to preserve muscle tissue even when energy is scarce, and it is the most satiating macronutrient — making the deficit far easier to sustain. At 1,600–2,000 kcal per day with 170+ g of protein, there is limited room for fat and carbohydrate — which is why cutting diets tend to be lean and precise.

Best Foods for a Cutting Phase

During a cut, you need foods that maximise protein and satiety per calorie — minimising the calorie cost of hitting your protein target so the remaining budget can be used on nutritious carbohydrates and fats:

• Chicken breast (skinless): 31 g protein per 100 g, only 165 kcal. The most calorie-efficient muscle-preserving protein available.
• 0% Greek yogurt: 10 g protein per 100 g, 57 kcal. Near-perfect for cutting — high protein, very low calorie, filling.
• Egg whites: 11 g protein per 100 g, 50 kcal. Buy cartons of liquid egg whites for convenience.
• Tinned tuna in spring water: 25 g protein per 100 g, 100 kcal. Fastest high-protein cutting food available.
• Cod or haddock (fresh or frozen): 18–20 g protein per 100 g, 80–90 kcal. Lower calorie than chicken breast.
• Non-starchy vegetables (broccoli, spinach, courgette, cucumber): 15–35 kcal per 100 g. Eat as much as you want — they add volume and micronutrients for almost no calorie cost.
• Rice cakes (plain): 35 kcal each. Low-calorie vehicle for protein spreads when you need a carbohydrate top-up.

Training During a Cut

Continue resistance training throughout your cut — this is the most important factor in preserving muscle mass. The training stimulus tells your body that muscle is needed and should be maintained. Without it, a calorie deficit will result in significant muscle loss alongside fat loss.

Reduce training volume by 20–30% during an aggressive cut (fewer sets, same weight) to manage recovery with limited energy. Avoid adding large amounts of new cardio on top of resistance training — excessive cardio on a calorie deficit accelerates muscle loss and makes recovery difficult. 2–3 cardio sessions per week of 30–45 minutes is appropriate alongside 3–4 resistance training sessions.