Cheapest Protein Sources UK: Cost Per 25g and 30g of Protein Compared
The cheapest food per 100g is not always the cheapest way to get protein. A food with a low headline price but low protein density can cost more per gram of protein than something that looks pricier at first glance. This guide compares 14 common UK protein sources by cost per 25g and 30g of protein, not just cost per pack.
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Cost Per Serving vs Cost Per Gram Of Protein
These are two different questions. "What is the cheapest protein food?" usually means cost per gram of protein: how much you pay to get a fixed amount of protein, regardless of what else is in the food. "What is the cheapest meal component?" is closer to cost per serving, which also reflects calories, volume and how filling something is.
A food can win on one measure and lose on the other. Eggs are one of the cheapest things you can buy per serving, but because eggs are only around 13% protein by weight, you need more eggs than you might expect to reach 25-30g of protein, which pushes their cost-per-protein-gram higher than foods with denser protein content like chicken, turkey or tinned fish.
Full Comparison Table
Prices are representative UK supermarket ranges (own-brand to mid-range), not live prices — see the note below the table. Figures use the same dataset as the site's Protein Value Comparator tool, so they will match if you check there too.
| Food | Protein per serving | Cost per serving | Cost per 25g protein | Cost per 30g protein |
|---|---|---|---|---|
| Lentils, cooked (200g) | 18g | 16-30p | 22-42p | 27-50p |
| Kidney beans, tinned (half a 400g tin) | 14g | 28-42p | 50-75p | 60-90p |
| Turkey mince, lean (125g raw) | 26.3g | 69p-£1.06 | 65p-£1.01 | 79p-£1.21 |
| Chicken thighs, boneless (150g raw) | 30g | 53-83p | 44-69p | 53-83p |
| Tinned tuna in spring water (1 tin) | 37.7g | 65p-£1.31 | 43-87p | 52p-£1.04 |
| Whey protein powder (1 scoop) | 23.4g | 50-80p | 54-86p | 65p-£1.03 |
| Chicken breast, raw (150g) | 33.8g | 68p-£1.05 | 50-78p | 60-93p |
| Tinned sardines in oil (1 tin) | 22.1g | 50-86p | 56-97p | 67p-£1.16 |
| Lean beef mince, 5% fat (125g raw) | 26.3g | 75p-£1.25 | 71p-£1.19 | 86p-£1.43 |
| Greek yogurt, 0%/low-fat (200g pot) | 20g | 46-76p | 58-95p | 69p-£1.14 |
| Firm tofu (half a block) | 23.3g | 68p-£1.05 | 73p-£1.13 | 87p-£1.35 |
| Skyr (200g pot) | 22g | 60-90p | 68p-£1.02 | 82p-£1.23 |
| Cottage cheese (half a 300g tub) | 18g | 53-83p | 73p-£1.15 | 88p-£1.38 |
| Eggs, large (2 eggs) | 14.6g | 58-75p | 99p-£1.29 | £1.19-£1.55 |
Why Lentils And Beans Look So Cheap Here
Lentils and beans are genuinely the cheapest protein per gram on this list, but they come with a real trade-off: lower protein density means a bigger portion is needed to hit the same protein total as meat, fish or eggs. 200g of cooked lentils gives about 18g of protein alongside a meaningful amount of carbohydrate and fibre, so lentils work best as part of a meal with another protein source rather than as your only protein for the day, unless you are comfortable eating large portions.
Best Choice Depending On Your Priority
There is no single "best" answer here — it depends what you are optimising for.
- Lowest cost per gram of protein: lentils, then kidney beans.
- Best balance of low cost and high protein density: turkey mince, chicken thighs, tinned tuna.
- Best if you want minimal prep: eggs and Greek yogurt, even though they cost slightly more per gram of protein.
- Best for batch cooking and freezing: chicken thighs, turkey mince, lean beef mince.
- Best shelf-stable option: tinned tuna, tinned sardines, tinned beans, whey protein powder.
- Best if you already use protein powder: it is genuinely cost-competitive with meat and fish per gram of protein, particularly when bought on sale or in bulk.
Common Mistakes When Comparing Protein Value
Comparing headline pack price rather than price per 100g leads to bad comparisons, since pack sizes vary a lot. Comparing cost per serving rather than cost per gram of protein is the other common mistake, which is exactly why eggs and Greek yogurt look cheaper than they really are once protein density is accounted for. Prices also vary meaningfully by retailer and promotion, so treat any single number as a starting point rather than an exact figure for your local shop.
Frequently Asked Questions
What is the cheapest way to get 25g of protein?
Lentils are usually the cheapest per gram of protein, at roughly 22-42p for 25g. Among denser protein sources, turkey mince, chicken thighs and tinned tuna are typically the best value, at roughly 43-87p for 25g.
Are eggs actually good value for protein?
Eggs are cheap per serving and very convenient, but their protein density is lower than meat or fish, so they cost more per gram of protein than most of the foods on this list. They are still a reasonable everyday choice, just not the cheapest by this specific measure.
Is protein powder cheaper than meat for protein?
Often yes, particularly when bought in bulk or on sale — whey protein powder frequently costs a similar or lower amount per gram of protein than chicken or beef mince. See the dedicated comparison for a full breakdown.
Do these prices reflect what I will pay in store?
No. These are representative ranges checked against real UK supermarket listings, not live prices. Actual cost depends on your retailer, pack size, brand and any current promotions.
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