Why Protein Matters

Protein is the most satiating macronutrient — it keeps you fuller for longer, reduces overall calorie intake, and preserves lean muscle mass during weight loss. It also has the highest thermic effect of food: your body burns 20–30% of protein calories just digesting it, compared to only 3–8% for carbohydrates and fat.

0.8g
Minimum protein per kg/day (UK RDA — the bare minimum, not optimal)
1.6–2.2g
Optimal range per kg/day for active adults and those building muscle
30%
of protein calories are burned during digestion (thermic effect)

Top 15 Animal Protein Sources

FoodProtein per 100gCalories per 100gNotes
Chicken breast (grilled)31g165Lean, versatile, affordable
Canned tuna (in water)26g109Best protein-per-penny ratio
Turkey breast29g135Leaner than chicken
Salmon (cooked)25g208High omega-3, excellent overall
Lean beef mince (5% fat)26g175Iron-rich, muscle-building
Prawns/shrimp24g99Very low calorie, high protein
Cod (cooked)23g105Lean white fish
Eggs (large)13g155Complete amino acid profile
Greek yoghurt (0% fat)17g97Gut-friendly, high casein
Cottage cheese11g98Slow-release protein (casein)
Parmesan cheese38g431Highest protein of all cheeses
Sardines (canned)22g208Budget-friendly, omega-3 rich
Pork tenderloin26g143Leanest cut of pork
Whey protein powder70–80g350–400Supplement, not whole food
Lamb (lean, cooked)25g218Iron and zinc-rich

Top 15 Plant Protein Sources

FoodProtein per 100gCalories per 100gNotes
Seitan (wheat gluten)25g370Highest plant protein by weight
Tempeh19g193Fermented soy, gut-friendly
Edamame (cooked)11g121Complete protein, great snack
Lentils (cooked)9g116Affordable, high fibre
Black beans (cooked)9g132Combine with rice for complete protein
Chickpeas (cooked)9g164Versatile, hummus base
Hemp seeds31g553Complete protein, omega-3 rich
Pumpkin seeds30g559High in zinc, complete amino acids
Quinoa (cooked)4g120Only complete plant grain protein
Tofu (firm)8–15g76Protein varies by firmness
Peanut butter25g588Calorie-dense, watch portions
Nutritional yeast50g325Complete protein, B12 source
Almonds21g579Good fats + protein combo
Oats (dry)17g389Best grain protein source
Green peas (frozen)5g81Inexpensive, high leucine
ℹ️ Complete vs Incomplete Protein
Complete proteins contain all 9 essential amino acids (all animal proteins + quinoa, soy, hemp, buckwheat). Incomplete proteins lack one or more. On a plant-based diet, eat varied protein sources throughout the day — you don't need to combine them at every meal, just across the day. Classic complete combinations: rice + beans, hummus + pita, peanut butter + oats.
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Frequently Asked Questions

How much protein can the body absorb per meal?
Research suggests the body can utilise approximately 20–40g of protein per meal for muscle protein synthesis. Higher amounts aren't wasted — they're used for other functions or oxidised — but 40g per sitting is generally considered a practical upper limit for muscle-building purposes. This is why spreading protein intake across 4–5 meals is recommended.
Is plant protein as good as animal protein for building muscle?
Plant proteins are generally lower in leucine — the key amino acid that triggers muscle protein synthesis. However, by eating higher quantities and combining sources, vegans can build muscle effectively. Studies show comparable muscle gain when total protein and leucine intake are matched between animal and plant-based diets.
What is the best time to eat protein?
Protein consumed within 2 hours after resistance training maximally stimulates muscle repair and growth. A high-protein breakfast also suppresses appetite throughout the day. Casein protein (from dairy) before bed provides slow-release amino acids during overnight recovery.

Related Health Guides

⚕️ Medical Disclaimer: This article is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional before making changes to your health routine or diet.
EC
Dr. Emma Clarke, PhD, RD
WellCalc Medical Contributor
All WellCalc articles are written and reviewed by qualified healthcare professionals. Our content follows current clinical guidelines from the NHS, AHA, WHO, and leading medical organisations.