The 10 Cheapest Keto Fats in the UK

A ketogenic diet relies on high fat intake, but this doesn’t mean expensive ingredients. The UK’s supermarkets offer several affordable options to meet your macros without straining your wallet. These ten fats cost less than £2.50 per 100g, with several under £1 – practical for weekly meal planning.

1. Butter (Salted or Unsalted)

At £1.35 for 250g at Lidl (54p per 100g), butter is one of the most cost-effective keto fats. It’s nearly 100% fat, with negligible carbs. Grass-fed versions like Kerrygold (£2.20 for 250g at Tesco) offer slightly higher omega-3 content but standard butter works fine for those prioritising budget.

2. Vegetable Oils (Rapeseed and Sunflower)

Rapeseed oil averages £1.80 per litre (18p per 100g) at Aldi. While not as high in saturated fats as coconut oil, it’s a neutral-tasting option for frying. Sunflower oil is similarly priced at £1.75 per litre in Sainsbury’s Basics range.

3. Lard

Traditional lard costs 90p for 250g at Morrisons (36p per 100g). It’s ideal for high-heat cooking and adds flavour to roasted vegetables. the best oils for keto cooking compares smoke points.

4. Double Cream

Supermarket double cream averages £1.20 for 300ml (40p per 100g). Asda’s own brand is often on offer at £1. Use it in coffee, sauces, or whipped with berries for dessert. Check for added thickeners in budget lines.

5. Cheddar Cheese (Mature or Extra Mature)

Mature cheddar provides more flavour per gram, meaning you use less. Tesco’s 400g block costs £2.20 (55p per 100g), while Aldi’s equivalent is £1.89. Cheese also delivers protein and calcium.

6. Mayonnaise (Full-Fat)

Hellmann’s Real Mayo is £2 for 400g (50p per 100g) at most supermarkets. Cheaper own-brand versions like Sainsbury’s Basics are 85p for 500g (17p per 100g). Avoid ‘light’ versions with added sugars.

7. Peanut Butter (100% Peanuts)

Meridian’s no-added-sugar peanut butter is £2.50 for 340g (74p per 100g) at Waitrose. Lidl’s 100% peanut version is £1.49 for 500g (30p per 100g). Measure portions carefully – nuts are calorie-dense.

8. Coconut Milk (Canned)

Asian supermarkets sell canned coconut milk for 75p per 400ml (19p per 100g), cheaper than UK chains. It’s ideal for curries and smoothies. Shake well before use as the fat separates.

9. Pork Scratchings

A 90g bag of pork scratchings costs £1 at Poundland (£1.11 per 100g). They’re pure fat and protein with zero carbs, though high in sodium. Look for ones without maltodextrin.

10. Flaxseeds (Whole or Ground)

At £1.50 for 200g (75p per 100g) in Aldi’s wholefoods section, flaxseeds offer omega-3s and fibre. Ground flax works as an egg substitute in baking. Store in the fridge to prevent rancidity.

What This Means in Practice

Autumn is prime time for stocking up – lard and butter prices drop as baking season begins. A weekly keto fat budget could include:

• 500g butter (£2.70)
• 1L rapeseed oil (£1.80)
• 300ml double cream (£1.20)
• 200g cheddar (£1.10)

Total: £6.80 for core fats, under £1 per day. Complement with budget keto protein sources like eggs and frozen chicken.

Frequently Asked Questions

Is margarine a good budget keto fat? No. Most margarines contain vegetable oils high in omega-6 fats and often include emulsifiers or sugars. Butter or ghee are better options for similar cost.

How do I calculate cost per 100g? Divide the item’s price by its weight in grams, then multiply by 100. For liquids like oil, 1ml ≈ 1g for this purpose.

Are seed oils bad on keto? While technically keto-friendly, over-reliance on high-omega-6 oils like sunflower may promote inflammation. Balance with omega-3s from flaxseeds or oily fish.

The Bottom Line

The UK’s supermarket chains make keto affordable if you focus on minimally processed fats. Seasonal buying and own-brand products can cut costs further. If you’d rather not do the macro maths yourself, the Keto Dieting app does it for you on Google Play and the App Store.

References

1. Bueno NB, de Melo IS, de Oliveira SL, da Rocha Ataide T (2013). Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. British Journal of Nutrition. https://doi.org/10.1017/S0007114513000548
2. Hyde PN, Sapper TN, Crabtree CD, et al. (2019). Dietary carbohydrate restriction improves metabolic syndrome independent of weight loss. JCI Insight. https://doi.org/10.1172/jci.insight.128308