What Are the Best Fats to Eat on Intermittent Fasting?

If you're doing intermittent fasting and constantly struggling with hunger, energy crashes, or slow results, there's a good chance your fat intake is either too low or coming from the wrong sources. Fat is the cornerstone of a successful fasting lifestyle — get it right and hunger becomes manageable, energy becomes stable, and fat loss accelerates.

The Short Answer

The best fats for intermittent fasting are animal fats and traditional cooking fats: ghee, butter, olive oil, coconut oil, and avocado oil. These stabilise blood sugar, reduce hunger, and support ketone production. Seed oils — sunflower, canola, vegetable oil — should be avoided completely. They drive inflammation, block fat burning, and work against everything you're trying to achieve during your fasting practice.

Why Fat Matters So Much During Fasting

When you're fasting, your body shifts from burning glucose to burning fat for fuel. This is called ketosis — and the quality of the fat you eat during your eating window has a direct effect on how smoothly that shift happens.

Healthy fats do three things that matter enormously for fasting:

1. They suppress hunger. Fat slows gastric emptying and reduces ghrelin (the hunger hormone). A meal rich in quality fats keeps you satisfied for 6–8 hours — long enough to extend your fasting window without fighting through cravings.

2. They keep insulin low. Fat has almost no effect on insulin compared to carbohydrates. Low insulin is the key to fat burning. When insulin stays low through your fasting window and rises only minimally during your eating window, your body burns stored fat for the majority of the day.

3. They fuel ketone production. Dietary fat is converted to ketones by the liver when insulin is low. Ketones provide nearly three times the energy of glucose and are associated with clearer thinking, stable mood, and sustained physical energy throughout your fast.

The Best Fats to Use

Ghee

Ghee is clarified butter with the milk solids removed. It has a high smoke point, making it excellent for cooking at high heat without oxidising. It contains butyrate — a short-chain fatty acid that feeds the gut lining, reduces intestinal inflammation, and supports the microbiome. Use it for frying eggs, sautéing vegetables, or as a cooking base for anything going in a hot pan.

Butter

Real butter from grass-fed cows contains conjugated linoleic acid (CLA), fat-soluble vitamins (A, D, E, K2), and short-chain fatty acids that support gut health and metabolic function. Unlike margarine or plant-based spreads, real butter is a whole food that has been part of human diets for thousands of years. Use it liberally on vegetables, stirred into soups, or on meat.

Extra Virgin Olive Oil

Cold-pressed extra virgin olive oil is one of the most studied fats in nutrition. It's rich in oleocanthal (a natural anti-inflammatory compound) and monounsaturated fatty acids that support cardiovascular health. It's best used for salad dressings, drizzling over cooked food, or low-to-medium heat cooking. Avoid cooking it at very high temperatures — its polyphenols break down above around 190°C (375°F).

Coconut Oil

Coconut oil is high in medium-chain triglycerides (MCTs), which the liver converts to ketones faster than other fats. This makes it particularly effective for deepening ketosis during the eating window. It's heat-stable, has antimicrobial properties, and works well for cooking, stir-frying, or blending into coffee.

Avocado Oil

Avocado oil has the highest smoke point of any common cooking fat — around 270°C (520°F) — making it the best choice for high-heat cooking. The fat in avocados is predominantly oleic acid (the same as olive oil). Avocados themselves are also one of the best fasting foods: loaded with potassium (which depletes during fasting as insulin drops), healthy fat, and fibre.

Fatty Cuts of Meat

When you eat meat during your eating window, choose fatty cuts: ribeye steak, lamb shoulder, duck breast, pork belly, bone-in chicken thighs. The fat in well-raised animals provides omega-3 fatty acids, fat-soluble vitamins, and CLA. Eating lean protein without fat is a common mistake during fasting — fat is the element that sustains satiety through the fasting window.

Eggs

Eggs are one of the most complete fat-and-protein combinations available. The yolk contains lecithin, choline (critical for brain and liver function), and healthy saturated fats. Two eggs cooked in ghee or butter is one of the most effective ways to open an eating window and set the body up for a long, hunger-free fast.

Fats to Eliminate Completely

The author of Intermittent Fasting in Practice is direct on this point: throw out all seed oils. That means sunflower oil, canola/rapeseed oil, vegetable oil, soybean oil, corn oil, and safflower oil. These oils are:

• Industrially processed — extracted via chemical solvents and high heat that damage the fat molecules before you open the bottle
• High in omega-6 — the body needs omega-6, but modern diets contain roughly 20 times more omega-6 than omega-3; this imbalance drives the chronic low-grade inflammation that makes fasting harder and fat loss slower
• Oxidation-prone — when heated, seed oils produce aldehydes and lipid peroxides linked to cellular damage and metabolic dysfunction

Also avoid margarine, "heart-healthy" spreads, and any product listing "partially hydrogenated" or "vegetable oil" as an ingredient. Most commercial salad dressings, mayonnaise, sauces, and restaurant cooking use seed oils — this is worth checking labels for carefully.

Practical Tips for Getting This Right

• Cook everything in ghee, butter, or coconut oil. Keep a jar of ghee on the stovetop within reach.
• Use olive oil cold or for gentle heat. Drizzle over salads, fish, and roasted vegetables after cooking.
• Eat half an avocado daily if possible. It addresses potassium deficiency, supports fat burning, and pairs with almost any meal.
• Don't fear the fat in meat. A fatty ribeye will extend the following day's fast far more effectively than lean chicken breast.
• Make your own sauces. Commercial versions almost universally contain seed oils. A sauce of olive oil, lemon juice, salt, and herbs takes two minutes and does the job better.

Book Callout

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Frequently Asked Questions

Can I add coconut oil or butter to coffee during my eating window?

Yes — adding coconut oil, MCT oil, or butter to coffee during your eating window supports ketone production and reduces hunger. Avoid adding fats during the fasting window itself, as they contain calories and can reduce the depth of the fast.

Is avocado oil better than olive oil?

They serve different purposes. Avocado oil has a higher smoke point and is better for high-heat cooking. Extra virgin olive oil has more polyphenols and anti-inflammatory compounds, making it better for raw use — dressings, drizzling, finishing. Use both.

How much fat should I eat per meal?

There's no rigid target, but fat should make up the majority of your plate calories if you're eating a fasting-compatible diet. A practical guide: a palm-sized protein portion, two tablespoons of cooking fat, and unlimited non-starchy vegetables dressed in olive oil. If you're hungry within 3–4 hours of eating, add more fat to your next meal.

Will eating more fat make me gain weight?

Dietary fat does not directly cause fat gain when insulin is low. Fat consumed in the absence of elevated insulin is used for energy, not stored. This is the mechanism that makes the combination of fasting (low insulin) and fat-focused eating so effective for fat loss.

What about nuts — are they a good fat source?

Nuts can be part of a fasting diet, but most varieties are high in omega-6 fatty acids that tip the inflammatory balance in the wrong direction. The better options are walnuts, pecans, macadamia nuts, and almonds. Use nuts occasionally rather than as a primary fat source, and hold off on them until you're near your target weight.

Related Articles

• What to eat during intermittent fasting
• Electrolytes and intermittent fasting
• How to break a fast correctly

This article is for informational purposes only and is not medical advice. Always consult a qualified healthcare professional before starting any fasting protocol, especially if you have an existing health condition.