Why protein is critical for weight loss
When you eat in a calorie deficit, your body draws energy from both fat stores and lean muscle tissue. Without adequate protein, a significant proportion of weight lost comes from muscle rather than fat — which slows your metabolism and makes the weight harder to keep off long-term.
Protein also has the highest thermic effect of any macronutrient: approximately 20–30% of protein calories are burned during digestion compared to 5–10% for carbohydrates and 0–3% for fat. This means that eating 200g of protein effectively delivers only 140–160g of usable calories after the digestive cost is accounted for.
Perhaps most importantly, protein is highly satiating. It suppresses ghrelin (the hunger hormone) and stimulates release of GLP-1 and PYY (fullness hormones) more powerfully than either carbohydrates or fat.
The evidence-based protein target for weight loss
The most current evidence — including systematic reviews from the International Society of Sports Nutrition — recommends 1.6–2.4g of protein per kg of body weight per day for people in a calorie deficit, particularly those who exercise.
| Body weight | Minimum (1.6g/kg) | Optimal (2.0g/kg) | High (2.4g/kg) |
|---|---|---|---|
| 60 kg | 96g | 120g | 144g |
| 75 kg | 120g | 150g | 180g |
| 90 kg | 144g | 180g | 216g |
If you are significantly overweight (BMI over 30), use your goal body weight rather than your current weight to calculate your target, as lean mass is a better predictor of protein needs than total mass.
Best high-protein foods to hit your target
Hitting 150–180g of protein per day sounds daunting, but it becomes straightforward once you build a core of high-protein staples into your daily diet.
- Chicken breast: 31g protein per 100g cooked
- Tinned tuna: 26g protein per 100g
- Eggs: 6g protein each (a 3-egg omelette = 18g)
- Greek yoghurt (0%): 10g protein per 100g
- Cottage cheese: 11g protein per 100g
- Salmon: 25g protein per 100g cooked
- Lentils: 9g protein per 100g cooked
- Tofu (firm): 8–12g protein per 100g
- Whey protein powder: 20–25g per scoop
How to spread protein throughout the day
The body can only use around 30–40g of protein per meal for muscle protein synthesis — though any amount is still used for other bodily functions. For optimal muscle preservation, spread protein across 3–5 meals rather than concentrating it in one or two large meals.
A practical approach for someone targeting 150g/day: 40g at breakfast (eggs + Greek yoghurt), 40g at lunch (chicken or fish), 35g at dinner (meat, fish, or legumes), and 35g from snacks (cottage cheese, protein shake, edamame).
Is high protein safe?
In healthy individuals without kidney disease, there is no credible evidence that protein intakes up to 3g/kg/day cause harm. The long-standing concern about kidney damage from high protein has been repeatedly examined in the literature and found to apply only to people with pre-existing renal conditions.
If you have existing kidney disease or a medical condition affecting protein metabolism, consult your doctor before significantly increasing protein intake.