What 100g of Protein a Day Costs: Aldi vs Tesco
The received wisdom on Aldi vs Tesco is simple: Aldi is the cheap one. If you are eating a lot of protein, that is where the savings are supposed to be. We tested it. On 8 October 2026 we priced the same protein staples at both shops using their own published shelf prices and unit prices, then worked out what hitting 100g of protein a day would cost from each. The answer is not what the reputation suggests, and the reason is a policy Tesco does not shout about on the shelf edge nearly as loudly as it could.
The headline: they are closer than you think
Across the protein staples we priced, Aldi and Tesco land within pennies of each other far more often than the reputation allows for. Tinned tuna is £2.49 for a four-pack at both. Tinned lentils are 45p at both. Peanut butter is 95p for 340g at both. Chicken thighs are £2.99 a kilo at both.
This is not coincidence. Tesco runs an Aldi Price Match programme, and its badge appears on exactly these items. If you are shopping for protein rather than for the whole weekly trolley, the choice between these two shops is much less consequential than choosing thigh over breast, or a tin of lentils over a block of tofu.
Where Aldi genuinely wins: ambient and own-brand dairy
The gaps appear wherever the price match does not reach. Aldi's 410g tin of baked beans is 27p against Tesco's 39p for 420g, which is 66p a kilo versus 93p, a 41% difference. Firm tofu is £4.75 a kilo at Aldi against £6.50 at Tesco, a 37% gap. A kilo of fat free Greek style yogurt is £1.49 at Aldi and £1.70 at Tesco, 14% apart.
Eggs follow the same pattern: a dozen medium free range are £2.49 at Aldi and £2.85 at Tesco, 21p an egg against 24p. None of these are large sums on a single shop. Repeated weekly across a household that eats a lot of yogurt and eggs, they add up to real money.
Where Tesco actually wins
One item went the other way, and it is worth reporting because it cuts against the premise. Tesco's 700g block of mature cheddar at £4.25 works out at £6.07 a kilo, slightly under Aldi's 400g block at £2.45, or £6.13 a kilo.
The mechanism is pack size rather than generosity: Tesco sells a bigger block, and the bigger block is better value per kilo. It is a reminder that per-kilo and per-pack are different questions, and that the unit price on the shelf edge is the only one worth reading. Tesco also had a wider range of larger packs generally, which is where a lot of its better per-kilo figures come from.
What 100g of protein a day actually costs
Take the cheapest sensible route to 100g of protein a day for a week. Built on tinned lentils, that is about £10.41 at Aldi and £10.59 at Tesco — a difference of 18p across a whole week. Built on tinned tuna it is £17.15 at either shop, identical.
Only when you build it on the unmatched items does the shop start to matter: a week of protein from baked beans is £9.24 at Aldi against £13.02 at Tesco. The practical reading is that your protein budget is set by what you put in the basket, and the supermarket is a rounding error unless you lean heavily on own-brand ambient goods.
The Clubcard complication
Every figure above is a standard shelf price. Tesco also runs Clubcard prices that are frequently lower: the 2kg bag of chicken thighs drops from £5.75 to £5.00 with a Clubcard, and plenty of other protein items carry a loyalty price.
We have deliberately left those out, because comparing a loyalty price against Aldi's everyday price is not a fair comparison, and because the offers expire. If you hold a Clubcard and shop the promotions, Tesco will often come out ahead of these numbers. If you do not, the figures above are what you pay.
How we worked it out
Prices came from Aldi's and Tesco's own online listings on 8 October 2026, using the unit prices the retailers publish on the shelf edge rather than ones we derived from pack sizes. Where a product is sold by drained weight, such as tinned tuna and pulses, we used the retailer's drained-weight figure.
Protein content is from the British Nutrition Foundation's protein resource. Because that source lists meat and fish cooked while the prices are per kilo raw, we adjusted for typical cooking weight loss; protein itself is not lost in cooking, only water. Grocery prices move constantly, so treat the ordering as the finding and the pennies as a snapshot.
Aldi vs Tesco turns out to be the wrong question for anyone shopping for protein. On most staples the two are level, and where they are not, the difference is smaller than the difference between two cuts of the same chicken. Remy adds up a recipe's ingredients into one shopping list and prices it across the supermarkets you actually shop at, so the comparison happens before you have filled the trolley.
Frequently asked questions
Is Aldi cheaper than Tesco for protein?
Marginally, and less often than you would expect. Tesco price-matches Aldi on chicken thighs, beef mince, tinned tuna, tinned lentils, chickpeas and peanut butter, so those are identical. Aldi wins clearly on baked beans, tofu, yogurt and eggs.
What is Tesco's Aldi Price Match?
A programme where Tesco matches Aldi's price on selected products, flagged with a badge on the product listing. On the protein staples we priced it covered a surprising proportion of the basket, which is why the two shops came out so close.
Should I use Clubcard prices when comparing?
Not for a like-for-like comparison. A Clubcard price is a loyalty price with an expiry date, so setting it against Aldi's everyday shelf price overstates the gap. If you have a Clubcard and shop the offers, though, Tesco will often beat the standard-price figures here.
What is the single biggest saving on protein?
Changing the cut, not the shop. Bone-in chicken thighs are £2.99 a kilo at both Aldi and Tesco, against roughly £6.15 to £6.66 for breast. That one swap saves more than switching supermarket does on almost any item we priced.