Kira Mei is a certified personal trainer and nutrition coach helping UK adults over 40 get fit, eat well, and build sustainable habits.
The supplement industry's most profitable lie is that protein is expensive. It is not. The cheapest protein sources available at Aldi and Lidl in the UK deliver protein at 2–4 pence per gram — a fraction of the 12–18 pence per gram charged by branded protein powders, and at a nutritional quality equivalent or better. Nutritionists charge by the hour to produce macro frameworks built entirely on supermarket staples that any adult can purchase and combine. The ranking below does the calculation directly: cost per 100 g of protein, using real current UK supermarket prices, so you can stop paying for information that should be free.
The cheapest protein per gram in the UK comes from tinned tuna (approximately 2.5p/g), chicken thighs (approximately 2.7p/g), and eggs (approximately 2.8p/g) — all available at Aldi or Lidl. BNF protein guidance and NHS Eatwell recommendations both support these whole-food sources as nutritionally complete. The weekly protein budget for a 75 kg adult needing 110 g per day is approximately £8–£10 from these three sources alone.
The Full UK Protein Cost Ranking
Ranked from cheapest to most expensive by cost per gram of protein, using current approximate Aldi and Lidl prices — the ranking that should replace every supplement advertisement your social media feed has ever served you.
1. Tinned Tuna in Spring Water — approx. 2.5p per gram of protein
Lidl Nixe tuna in spring water: 145 g tin for approximately 69p. Each tin contains approximately 28 g of protein. Cost per gram: 69p ÷ 28 = approximately 2.5p. Four tins per week = 112 g protein = approximately £2.76. This is the most efficient protein source in any UK supermarket. BNF identifies oily and white fish as complete protein sources containing all essential amino acids. Tinned tuna in spring water is not a compromise — it is the optimal budget protein.
2. Chicken Thighs (Boneless) — approx. 2.7p per gram of protein
Lidl Birchwood Farm boneless chicken thighs: approximately £3.49/kg. Cooked, approximately 70% of the raw weight remains (water loss during cooking). Per 100 g cooked weight: approximately 25 g of protein. Per 100 g raw weight: approximately 17 g. Cost per gram cooked protein: approximately 2.7p. For comparison, chicken breast delivers approximately 22 g protein per 100 g raw at approximately £5.50/kg = approximately 2.5p/g raw — similar to thigh when cooked-weight is normalised. Thigh wins on flavour and moisture retention.
3. Eggs — approx. 2.8p per gram of protein
Aldi free-range medium eggs: £1.39 for six (approximately 23p per egg). Each egg provides approximately 8 g of protein. Cost per gram: 23p ÷ 8 = approximately 2.9p. Eggs are the most versatile source in this list: eaten raw (blended into a shake), scrambled in five minutes, or batch hard-boiled for the week. They provide a complete amino acid profile, vitamin D, B12, and selenium alongside the protein. Hard to beat for nutritional breadth at this cost.
4. Tinned Mackerel in Brine — approx. 3.0p per gram of protein
Aldi tinned mackerel in brine: approximately £0.79 per 125 g tin. Protein content: approximately 20–22 g per tin. Cost per gram: approximately 3.6p. Mackerel is higher in fat (omega-3 fatty acids) than tuna, providing additional nutritional benefit not captured in pure cost-per-gram comparisons. An excellent complement to tuna in a weekly rotation for omega-3 coverage. BNF specifically recommends oily fish at least twice per week.
5. Greek Yoghurt 0% Fat — approx. 3.5p per gram of protein
Aldi Brooklea 0% Greek yoghurt: approximately £1.45 per 500 g. Protein per 100 g: approximately 10 g. Protein per 500 g tub: approximately 50 g. Cost per gram: £1.45 ÷ 50 = approximately 2.9p. The advantage of Greek yoghurt over meat proteins is zero cooking required, no refrigeration issues during the day (in an insulated bag), and ease of combination with oats or fruit for breakfast. Two 200 g servings per day = 40 g protein = approximately £1.16.
6. Cottage Cheese — approx. 3.8p per gram of protein
Aldi cottage cheese: approximately £1.29 per 300 g. Protein per 100 g: approximately 11 g. Total protein per pot: approximately 33 g. Cost per gram: £1.29 ÷ 33 = approximately 3.9p. Cottage cheese is slower-digesting than most protein sources (casein-based), making it a useful pre-sleep protein option. Under-used by most UK adults despite being widely available and highly cost-effective.
7. Chicken Breast — approx. 2.5p per gram (raw) / 3.8p (cooked weight adjusted)
Lidl Birchwood Farm chicken breast: approximately £5.40/kg. Per 100 g raw: approximately 22 g protein. Raw cost per gram: approximately 2.5p. However, chicken breast loses approximately 30–35% of its weight during cooking — the cooked cost per gram is closer to 3.8p. Factor this into your calculations. Chicken breast remains an excellent protein source but is not the bargain it appears on raw price alone.
8. Baked Beans — approx. 4.5p per gram of protein
Aldi baked beans: approximately £0.29 per 400 g tin. Protein per tin: approximately 16 g. Cost per gram: approximately 1.8p. This appears to beat the list above — but baked beans are a partial protein (low in methionine) and should not be used as the sole protein source. Combined with eggs or tuna, they are an excellent and extremely cheap complementary protein and fibre source. On a pure cost-per-gram basis, unbeatable for plant-based protein.
How to Use the Rankings to Build a Cheap High-Protein Week
The optimal UK budget protein strategy is not to rely on the single cheapest source but to combine the top four — tinned tuna, chicken thighs, eggs, and Greek yoghurt — across each day, providing complete amino acid coverage and nutritional variety for approximately £2.00–£2.50 per day in protein costs alone.
Daily Protein Stack for Under £3 (75 kg Adult, 110 g Target)
Breakfast: 200 g Greek yoghurt with oats = 20 g protein (approx. 58p). Lunch: 1 tin of tuna with rice and veg = 28 g protein (approx. 69p). Snack: 2 hard-boiled eggs = 16 g protein (approx. 46p). Dinner: 200 g cooked chicken thigh with vegetables = 50 g protein (approx. £1.00). Total: 114 g protein for approximately £2.73 in protein costs. Under the 110 g target for a 75 kg adult. Well under £3 per day.
Rotating Sources to Avoid Flavour Fatigue
Tinned tuna every day is effective but monotonous. A practical weekly rotation: Monday and Wednesday — chicken thighs. Tuesday and Thursday — tinned tuna. Friday — salmon (Lidl fillets approx. £3.99 for two). Daily eggs and Greek yoghurt at breakfast or snack. This rotation provides variety, covers omega-3 intake (mackerel or salmon twice weekly), and stays within budget.
Vegetarian and Plant-Based on a Budget
The cheapest plant-based protein sources in UK supermarkets: dried red lentils (Aldi, approximately £1.49/kg, 24 g protein per 100 g dry = approximately 0.6p/g dry, 1.8p/g cooked); tinned chickpeas (approximately £0.45 per 400 g tin, 10 g protein per tin = approximately 4.5p/g); tofu (approximately £1.39 per 280 g block, 10 g protein per 100 g = approximately 5.0p/g). Plant proteins are typically lower in cost per gram than animal proteins but require combination across the day to achieve a complete amino acid profile. BNF recommends plant-protein diversity specifically for this reason.
What to Avoid: Expensive Protein Sources That Add No Nutritional Benefit
Branded protein powders, "high-protein" convenience foods, and specialist sports nutrition products typically deliver protein at 12–18p per gram — four to seven times the cost of equivalent protein from whole foods at Aldi or Lidl, with no evidence of superior outcomes for most UK adults.
Protein Powder: Worth It or Not?
Whey protein powder costs approximately 2.5–4p per gram of protein depending on brand and source — comparable in cost to whole-food sources. For UK adults who consistently struggle to hit their daily protein target from whole food, whey protein is a practical supplement. For those who can build a diet around chicken, eggs, and Greek yoghurt, it is unnecessary. The whole-food sources listed above also provide micronutrients, satiety, and culinary flexibility that protein powder does not.
"High-Protein" Branded Products
Supermarket-branded "high-protein" yoghurts, bars, and ready meals typically contain 15–20 g of protein at £1.50–£2.50 per unit — approximately 7.5–17p per gram of protein. The same protein content is available in a tin of tuna at 69p. The premium goes to branding and packaging, not nutrition. MSE grocery guides document the consistent mark-up on "functional food" products across UK supermarkets.
Specialist Bodybuilding Foods
Beef jerky, protein bars, and recovery shakes sold through specialist retailers cost 15–30p per gram of protein. Some are excellent products for specific use cases (portable, no refrigeration, quick digestion). None are necessary for UK adults building a budget high-protein diet. They are convenience products at a significant premium.
FAQ
What is the cheapest protein per gram in the UK?
Tinned tuna in spring water from Aldi or Lidl (approximately 2.5p per gram), followed by boneless chicken thighs (approximately 2.7p/g), eggs (approximately 2.9p/g), and 0% Greek yoghurt (approximately 2.9p/g). These four sources, combined across the day, cover the 1.4–2.0 g/kg protein target recommended by BNF for adults in strength programmes for approximately £2.50–£3.00 per day in protein costs alone.
Is protein powder cheaper than food in the UK?
At approximately 2.5–4p per gram, mid-range whey protein is comparable in cost to tinned tuna and chicken on a pure protein-per-gram basis. However, whole-food sources provide additional micronutrients, greater satiety, and more culinary flexibility. For UK adults who can consistently hit protein targets from whole food, protein powder is an unnecessary expense. For those who cannot, it is a practical supplement — not a superior choice.
How much protein should I aim for per day on a budget UK?
1.4 g per kg of bodyweight per day for adults in strength training, or 0.75 g/kg for sedentary adults, per BNF guidelines. For a 75 kg active adult, that is approximately 105 g per day — achievable for approximately £2.50–£3.00 from tinned tuna, chicken, eggs, and Greek yoghurt at Aldi or Lidl. The NHS Eatwell Guide recommends protein at every meal to support this distribution.
What is the best budget protein source for building muscle in the UK?
Tinned tuna in spring water and eggs represent the best combination of cost, completeness (all essential amino acids), and versatility for UK adults building muscle on a budget. Tinned tuna provides 28 g protein per 69p tin; eggs provide 8 g protein per 23p egg. Combined with chicken thighs at £3.49/kg, these three sources cover the full protein requirement for a 75–80 kg adult in a strength programme for under £4 per day.
Can plant-based protein be as cheap as meat in the UK?
Yes, on a cost-per-gram basis. Dried red lentils at Aldi (approximately £1.49/kg, 24 g protein per 100 g dry) are among the cheapest protein sources available. However, plant proteins are typically incomplete — they lack one or more essential amino acids — and require combination across the day to achieve full protein quality. BNF guidance recommends plant-protein diversity for this reason. Kira Mei's Nutrition Blueprint gives you the macro framework, meal prep system, and UK supermarket strategy — one purchase, no subscription. Available at kiramei.co.uk.
Disclaimer: This article is for informational purposes only and does not constitute medical, nutritional, or professional fitness advice. Always consult a qualified healthcare professional before making changes to your diet or exercise routine.