Healthy Fats for Weight Loss: A UK Guide

Healthy fats for weight loss are a key part of a balanced, sustainable diet, yet many people remain uncertain about which fats to choose and how much to eat. Not all dietary fats are equal: unsaturated fats found in oily fish, nuts, avocados, and olive oil can support satiety and nutrient absorption, while trans fats and excess saturated fats are best minimised. UK guidance from the NHS and SACN has moved away from blanket low-fat advice, instead emphasising fat quality within an overall calorie-controlled diet. This article explains which fats help, which to limit, and how to include them practically.

What are healthy fats and why do they matter for weight loss?

Healthy fats, mainly unsaturated fats from plant and marine sources, support weight loss by promoting satiety and aiding absorption of fat-soluble vitamins A, D, E, and K, without undermining calorie control when eaten in appropriate portions.

Healthy fats, primarily unsaturated fats found in plant and marine sources, can support weight management by promoting satiety, and by helping the body absorb fat-soluble vitamins such as A, D, E and K.^[1][2] Dietary fat is not the enemy of weight management; rather, the type and quantity of fat consumed makes the meaningful difference. UK guidance, including the NHS Eatwell Guide and advice from the Scientific Advisory Committee on Nutrition (SACN), has moved away from blanket low-fat recommendations towards an emphasis on fat quality within an overall balanced diet.^[10][9]

Unsaturated fats fall into two main categories: monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). MUFAs, found in olive oil and avocados, are associated with maintaining healthy cholesterol levels.^[7][14] PUFAs include omega-3 and omega-6 fatty acids, which are associated with cardiovascular health; these associations are recognised by the British Heart Foundation and reflected in SACN's 2019 report on saturated fats and health. Both types can form part of a calorie-controlled diet without undermining weight loss goals.

Fat is the most energy-dense macronutrient, providing around 9 kilocalories per gram compared with around 4 kilocalories per gram for carbohydrates and protein (NHS: Fat: the facts).^[1][10] This means portion awareness remains important even when choosing healthier fat sources. Because fat slows gastric emptying and can contribute to feelings of fullness, moderate inclusion of healthy fats in meals may help reduce overall calorie intake by curbing hunger between meals, though individual responses vary. The NHS Eatwell Guide acknowledges that total fat intake should be considered within the context of overall dietary balance rather than eliminated entirely.

Which foods contain the best fats for managing your weight?

Oily fish, nuts, seeds, avocados, extra virgin olive oil, and rapeseed oil are the best fat sources for weight management, providing unsaturated fatty acids alongside fibre, protein, and micronutrients.

The foods richest in beneficial fats for weight management include oily fish, nuts, seeds, avocados, and oils such as extra virgin olive oil and rapeseed oil. These sources provide unsaturated fatty acids alongside other nutrients, including fibre, protein, and micronutrients, that collectively support a healthy, sustainable diet.

Oily fish such as salmon, mackerel, sardines, and trout are particularly valuable because they supply long-chain omega-3 fatty acids (EPA and DHA), which are associated with heart health benefits. The NHS recommends eating at least two portions of fish per week, one of which should be oily (NHS: Fish and shellfish).^[6] Where possible, choose fish that is grilled, baked, or steamed rather than battered or breaded, to avoid adding unnecessary calories and salt.

Nuts and seeds, including walnuts, almonds, flaxseeds, and chia seeds, provide plant-based omega-3s (ALA), fibre, and protein, making them satisfying snacks that can help manage appetite. Choose unsalted varieties where available to keep sodium intake in check. Avocados are a rich source of MUFAs and also provide potassium and dietary fibre. Extra virgin olive oil, a cornerstone of the Mediterranean dietary pattern, contains oleic acid and polyphenols; the British Heart Foundation notes that the Mediterranean diet, which features olive oil prominently, is associated with reduced cardiovascular risk. Rapeseed oil is a cost-effective UK alternative with a favourable fatty acid profile and is suitable for everyday cooking.

• Oily fish (salmon, mackerel, sardines): omega-3 EPA and DHA

• Nuts and seeds (walnuts, almonds, chia, flaxseed): plant-based omega-3 ALA, fibre; choose unsalted

• Avocado: MUFAs, potassium, fibre

• Extra virgin olive oil and rapeseed oil: MUFAs, polyphenols

Portions still matter. A small handful of nuts (roughly 30 g) or one tablespoon of oil per serving are practical examples from the British Dietetic Association (BDA) to help avoid inadvertently exceeding calorie targets.^[8]

How much fat should you eat each day if you're trying to lose weight?

UK guidelines recommend total fat should not exceed 35 per cent of dietary energy, with saturated fat below 11 per cent; on a 2,000 kcal diet this means no more than approximately 78 g total fat and 24 g saturated fat daily.

UK dietary guidelines from the Scientific Advisory Committee on Nutrition (SACN) and the Government Dietary Recommendations (Public Health England) recommend that total fat should provide no more than 35 per cent of total dietary energy intake, with saturated fat kept below 11 per cent of total energy.^[9][5] For an average adult consuming around 2,000 kilocalories per day, this equates to no more than approximately 78 g of total fat and no more than around 24 g of saturated fat daily.^[9][10] When aiming to lose weight on a reduced-calorie intake, these proportions remain a useful guide even as absolute gram targets decrease.

There is no single universally prescribed fat intake for weight loss, and individual needs vary depending on age, sex, activity level, and any underlying health conditions. Some people follow moderate-fat dietary patterns such as the Mediterranean diet, which derives a higher proportion of calories from fat, predominantly unsaturated, and this approach has evidence supporting cardiovascular health and sustainable weight management, as summarised by the British Heart Foundation. Others follow lower-fat approaches. Both can be effective when overall calorie balance is appropriate.

Practical strategies for managing fat intake without eliminating it include:

• Measuring oils rather than pouring freely, as liquid fats are easy to over-use

• Choosing cooking methods such as grilling, steaming, or baking over deep-frying

• Reading food labels and comparing the saturated fat content per 100 g; the NHS traffic-light labelling system can help identify high, medium, and low fat content at a glance

• Prioritising whole food fat sources (nuts, fish, avocado) over processed products with added fats

If you have a specific health condition such as type 2 diabetes or cardiovascular disease, a registered dietitian can provide personalised guidance on fat intake targets aligned with your clinical needs.

Are there any fats you should still avoid on a weight loss diet?

Trans fats and excess saturated fats, found in processed baked goods, butter, fatty meats, and coconut oil, should be minimised as they raise LDL cholesterol and increase cardiovascular risk.

Trans fats and excessive saturated fats are the types most strongly associated with adverse health outcomes and are best minimised on any diet, including one aimed at weight loss. Trans fats, formed during the partial hydrogenation of vegetable oils, raise LDL (bad) cholesterol and lower HDL (good) cholesterol, increasing cardiovascular risk.^[11][12] The Food Standards Agency (FSA) has worked with industry to reduce artificial trans fats in processed foods, and they are now far less prevalent than in previous decades, but they can still appear in some imported products and certain commercially produced baked goods.^[11]

Saturated fats, found in butter, lard, full-fat dairy, fatty cuts of meat, coconut oil, and palm oil, are not entirely harmful in small amounts, but consuming them in excess is associated with raised LDL cholesterol. The NHS advises swapping saturated fats for unsaturated alternatives where possible, rather than simply adding unsaturated fats on top of an already high saturated fat intake (NHS: Saturated fat).^[4]

It is also worth being cautious about:

• Ultra-processed foods marketed as "low fat", which often compensate with added sugar and salt, potentially undermining weight loss efforts

• Coconut oil, which is high in saturated fat despite being widely promoted as a health food; the NHS and the British Heart Foundation do not support its use as a primary cooking fat^[4]

• Heavily processed meat products such as sausages and pies, which combine saturated fat with high sodium and calorie content

If you have a nut or fish allergy, a registered dietitian can advise on suitable alternative sources of healthy fats.

For people considering structured weight management support, including dietary advice alongside other interventions, speaking with a GP or registered dietitian is the appropriate first step. Where medication is being considered as part of a broader weight management plan, a prescriber can assess clinical suitability through a consultation; Bolt Pharmacy is a GPhC-registered UK online pharmacy offering online weight-management consultations, with prescriber review and pharmacist support, where clinically appropriate options may be discussed.

Scientific References

1. Facts about fat.
2. Fat facts – British Dietetic Association.
3. Prevention of CVD: saturated and unsaturated fats evidence paper.
4. How to eat less saturated fat.
5. Saturated fats and health: SACN report.
6. Fish and shellfish.
7. Cholesterol – British Dietetic Association.
8. Portion sizes – British Dietetic Association.
9. SACN statement on expressing energy, fat and carbohydrate intakes and recommendations.
10. The Eatwell Guide.
11. Prevention of cardiovascular disease at population level: trans fats evidence paper.
12. Meta-regression analysis of the effects of dietary cholesterol intake on LDL and HDL cholesterol.
13. Is there a linear relationship between the dose of ruminant trans-fatty acids and cardiovascular risk markers in healthy subjects.
14. Effects of high-oleic dietary interventions on cardiometabolic outcomes in adults: a GRADE-based systematic review and meta-analysis of randomised controlled trials.

Frequently Asked Questions