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 depends on you believing that real protein is expensive. A single tub of whey protein at £35 for 30 servings — roughly £1.17 per 25 g protein serving — is routinely marketed as "the affordable option." Walk into Aldi and buy a 1.5 kg pack of chicken thighs for £3.49, and you're paying approximately 4p per gram of cooked protein. The supplement is not competing on price. It never was. The cheap protein foods in UK supermarkets are not a secret — they just require someone to do the arithmetic rather than trust the packaging.
Quick Answer: The cheapest protein foods in UK supermarkets by cost-per-gram are: tinned chickpeas (Aldi, ~3p per gram of protein), eggs (Aldi, ~3.5p per gram), chicken thighs (Aldi, ~4p per gram cooked), tinned tuna (Aldi, ~4.5p per gram), and red lentils (Lidl, ~5p per gram). All are available fresh or shelf-stable and require minimal preparation.
How to Read a Protein Price Comparison Properly
Cost-per-gram of protein is the only number that matters when comparing protein foods — not cost per pack, not cost per calorie.
A 400 g tin of chickpeas at £0.47 (Aldi own-brand) contains approximately 19 g of protein when drained (roughly 7 g per 100 g drained weight). That works out to 2.5p per gram of protein — one of the best ratios in any UK supermarket. A chicken breast at £5.50 per kilogram delivers approximately 31 g of protein per 100 g cooked, or roughly 1.8p per gram. Chicken breast is, in fact, cheaper per gram of protein than chickpeas at full price — but the comparison flips entirely when chickpeas are tinned and priced correctly.
Why Raw Versus Cooked Weight Changes Everything
Chicken loses approximately 25–30% of its weight during cooking due to water loss. A 200 g raw chicken thigh becomes approximately 140–150 g cooked. That changes the cost-per-gram calculation significantly. All cost-per-gram figures in this post use cooked or drained weights where applicable, not raw packet weights.
What the British Nutrition Foundation Says About Protein Sources
According to the British Nutrition Foundation, both animal and plant protein sources contribute to daily protein requirements. Combining plant sources — such as legumes and wholegrains — across the day provides all essential amino acids. This matters for the cost comparison: the cheapest protein sources by gram are often plant-based, and they are nutritionally complete when combined appropriately.
Why Supplement Marketing Inflates Perceived Costs
The supplement industry markets protein per serving (typically 25–30 g) as the unit of comparison. Real food is sold per gram of total product weight. The arithmetic required to compare these is deliberately obscured. A 1 kg bag of red lentils (Lidl, £0.89) contains approximately 225 g of protein across the full bag — that's 0.4p per gram. A mid-tier whey protein at £25 for 1 kg (with roughly 75% protein content) costs 3.3p per gram. The red lentils are eight times cheaper per gram of protein.
The Full Cost-Per-Gram Rankings at UK Supermarkets
All prices are from Aldi, Lidl, and Tesco UK. All protein content is from British Nutrition Foundation food tables or standard UK nutritional data. All costs use cooked or drained weights.
Tier 1: Under 4p Per Gram of Protein
| Food | Supermarket | Pack Price | Pack Size | Protein Per 100g | Cost Per Gram Protein |
|---|---|---|---|---|---|
| Red lentils (dry) | Lidl | £0.89 | 500 g | 9 g (cooked) | ~2p |
| Tinned chickpeas | Aldi | £0.47 | 400 g (drained ~240g) | 7 g | ~2.8p |
| Split peas (dry) | Tesco | £0.95 | 500 g | 8 g (cooked) | ~2.4p |
| Eggs (medium, 12pk) | Aldi | £2.19 | 12 eggs | 13 g per 100 g | ~3.5p |
| Tinned kidney beans | Aldi | £0.45 | 400 g (drained ~240g) | 6.9 g | ~2.7p |
Red lentils at Lidl are consistently the cheapest protein food per gram in any UK supermarket, including discount chains. The Money Saving Expert repeatedly identifies dried legumes as the best value protein category in UK grocery shopping.
Tier 2: 4–7p Per Gram of Protein
| Food | Supermarket | Pack Price | Pack Size | Protein Per 100g (cooked) | Cost Per Gram Protein |
|---|---|---|---|---|---|
| Chicken thighs bone-in | Aldi | £3.49 | 1.5 kg | ~25g (cooked, skinless) | ~4p |
| Tinned tuna (spring water) | Aldi | £0.72 (single) | 145 g | ~25 g | ~4p |
| Tinned mackerel | Aldi | £0.79 | 125 g | ~20 g | ~3.2p |
| Frozen chicken breast | Lidl | £4.49 | 1 kg | ~31 g | ~4.5p |
| Whole milk (per 100 ml protein) | Aldi | £1.19 | 2 L | 3.4 g | ~5p |
| Skyr yoghurt | Lidl | £1.49 | 500 g | 10 g | ~3p |
Tinned mackerel is frequently overlooked but delivers an excellent cost-per-gram ratio alongside a meaningful omega-3 contribution — a benefit not captured in the protein-only comparison.
Tier 3: 7–12p Per Gram of Protein
| Food | Supermarket | Pack Price | Pack Size | Protein Per 100g | Cost Per Gram Protein |
|---|---|---|---|---|---|
| Chicken breast (fresh) | Aldi | £3.49 | 640 g | 31 g | ~5.6p |
| Tofu (firm) | Tesco | £1.75 | 280 g | 8 g | ~7.8p |
| Frozen salmon fillet | Lidl | £4.49 | 4-pack (~480g) | 20 g | ~7p |
| Greek yoghurt | Aldi | £1.39 | 500 g | 5.7 g | ~4.9p |
| Cottage cheese | Aldi | £0.99 | 300 g | 12.4 g | ~2.7p |
Cottage cheese at Aldi (£0.99 for 300 g) is underrated: 12.4 g protein per 100 g places it in Tier 1 territory on cost-per-gram, but it has limited use in batch cooking, which is why it sits here as a snack option.
The Practical Ranking: What to Actually Buy
Cost-per-gram is the decision framework, but practicality filters the final list.
Best Overall Protein Foods for Budget Batch Cooking in the UK
- Chicken thighs (Aldi, £3.49/1.5 kg) — versatile, batch-cookable, freezeable, excellent flavour, strong cost-per-gram
- Eggs (Aldi, £2.19/12) — fastest to cook, no prep, portable, lowest barrier to daily use
- Red lentils (Lidl, £0.89/500 g) — cheapest per gram, require no refrigeration, cook in 20 minutes, mix into almost any meal
- Tinned tuna (Aldi, £2.89/4-pack) — zero cooking required, portable, mixes with rice, pasta, or salad directly from the tin
- Tinned chickpeas (Aldi, £0.47/400 g) — no cooking required, roastable for texture, bulk-buyable
What to Avoid on a Budget (Higher Cost, Lower Protein)
- Protein bars — most UK brands deliver 20 g protein at £1.50–£2.50 per bar, or 7–12p per gram. Far more expensive than any whole-food option on this list.
- Pre-marinated chicken breasts — Tesco and Sainsbury's pre-marinated options often cost £5–£6 per kilogram versus £3.49 for plain thighs at Aldi. The marinade cost is embedded; the protein content is lower (less meat per pack due to water injection).
- Deli meats — sliced cooked chicken, turkey, and ham at supermarket counters run £10–£14 per kilogram. The protein content is identical to the whole roasted equivalent at a fraction of the price.
The NHS Eatwell Position on Protein Variety
The NHS Eatwell Guide recommends varying protein sources to include both animal and plant options. A practical interpretation for budget shoppers: anchor two or three days per week on chicken thighs or eggs, and the remaining days on legumes or canned fish. This rotation costs less than a single-protein approach (no over-reliance on any one animal product) and covers a broader amino acid profile.
How to Combine Budget Proteins to Build a Full Week
Protein diversity costs nothing extra if you plan the rotation before the shop.
A Sample Five-Day Protein Rotation Under £12
- Monday and Tuesday: Chicken thighs (1.5 kg pack covers both days)
- Wednesday: Tinned tuna (two tins, mixed into rice) — £0.72 × 2 = £1.44
- Thursday: Red lentil dhal with eggs — £0.89 lentils + £0.73 in eggs (4 eggs) = £1.62
- Friday: Tinned mackerel with sweet potato and spinach — £0.79
Protein anchor cost for the full week: approximately £7.23. Remaining budget covers carbohydrates, vegetables, and breakfast.
Why Variety Matters for Adherence
The British Nutrition Foundation notes that dietary adherence over weeks and months is as important as the nutritional composition of any single meal. Rotating protein sources prevents the flavour fatigue that causes budget meal prep habits to break down by week three. The cost of that rotation is negligible; the benefit to consistency is significant.
Buying in Bulk: When It Actually Saves Money
Tinned goods (chickpeas, tuna, mackerel, kidney beans) are always worth buying in multipack quantities at Aldi or Lidl when on offer. A 4-pack of tuna at £2.89 (£0.72 per tin) is a modest saving over individual purchase; a 6-pack when on offer at £3.99 (£0.67 per tin) extends the saving further. Shelf-stable proteins are the one category where stockpiling makes sense. Fresh chicken should be batch-bought and frozen — Aldi's 1.5 kg packs freeze well when split into single-day portions before freezing.
Frequently Asked Questions
What is the cheapest protein food per gram in UK supermarkets?
Red lentils are consistently the cheapest protein food per gram available in UK supermarkets. Lidl sells a 500 g bag for £0.89; when cooked, the full bag yields approximately 225 g of protein at a cost of approximately 0.4p per gram of protein. Tinned kidney beans and chickpeas (Aldi, £0.45–£0.47 per tin) are close rivals in the tier-1 bracket. The British Nutrition Foundation confirms legumes as a high-quality plant-based protein source appropriate for regular inclusion.
Is tinned tuna a good protein source for the price?
Yes. Aldi tinned tuna in spring water costs approximately £0.72 per 145 g tin and delivers around 25 g of usable protein per tin — approximately 2.9p per gram. It requires no cooking, no refrigeration before opening, and mixes easily with rice, pasta, or salad. The Money Saving Expert consistently identifies canned fish as one of the best cost-per-serving protein options in UK budget supermarkets.
Are eggs still worth it as a protein source in the UK?
Yes. At £2.19 for a 12-pack at Aldi (May 2026 pricing), eggs deliver approximately 6.5 g of protein per egg, or roughly 3.5p per gram of protein. They are one of the most complete amino acid profiles of any food, require minimal cooking time, and work in every meal slot from breakfast through to dinner. The NHS Eatwell Guide includes eggs as a recommended protein source within a balanced diet.
Does chicken breast or chicken thigh give more protein per pound spent?
Chicken thigh bone-in gives more protein per pound spent when accounting for cooking loss correctly. Fresh chicken breast at Aldi costs approximately £5.50 per kilogram raw, delivering 31 g protein per 100 g cooked. Bone-in thighs at £3.49/1.5 kg deliver approximately 25 g per 100 g cooked flesh. The breast wins on raw protein density, but the thigh wins significantly on cost-per-gram protein when both are priced correctly: thigh works out to approximately 4p per gram protein versus 5.6p for fresh breast.
Are protein foods from Aldi and Lidl nutritionally equivalent to those from more expensive supermarkets?
Yes. The macronutrient composition of chicken, eggs, lentils, and tuna does not vary by supermarket brand. A chicken thigh from Aldi contains the same protein as a chicken thigh from Waitrose — the difference is the welfare standard, feed type, and traceability, not the macronutrient profile. For budget meal prep where cost-per-gram is the primary metric, Aldi and Lidl own-brand products are nutritionally interchangeable with premium equivalents.
Kira Mei's Nutrition Blueprint contains the full cost-per-gram framework, the UK supermarket strategy, and the batch cooking system built around these rankings — one purchase, no subscription, no meal plan to follow forever. It's not a diet plan, it's a textbook.
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.