Best Fats for Weight Loss: What to Eat & Avoid

Olive oil, nuts, avocado, fatty fish and seeds. None of them burns fat. All of them help. Five fats worth eating, three to limit, and the measuring habit that decides whether healthy fat helps or quietly adds 300 calories.

Jump to List Shop

Staci Gulbin, MS, MEd, RDRegistered Dietitian · Dec 4, 2022

Everyday Maintenance Meal Plan box from Clean Eatz Kitchen with plated meals

Quick answer

The best fats for weight loss are unsaturated fats from olive oil, nuts, avocado, fatty fish and seeds. They don't burn fat. They make meals satisfying and support heart health when they replace butter, processed foods or refined carbs. Keep fat at 20 to 35% of calories, about 44 to 78g on 2,000 calories, and measure oils and nut butters, because a tablespoon of oil is 120 calories.

Fat spent decades as the villain of weight loss. Low-fat everything filled the shelves, and people avoided avocados like they were pure cholesterol. That advice didn't hold up.

Dietary fat doesn't automatically become body fat. Extra calories do, whether they come from fat, carbs or protein. What fat does is make food satisfying, and satisfying food is easier to stick with.

Below are the five fats worth building meals around, ranked by how strong the evidence is and how easy they are to use, then the three to limit and the habits that keep healthy fats from becoming a calorie problem.

Why fat doesn't make you fat

A salad with olive oil and nuts keeps you full for hours. The same salad with fat-free dressing can leave you raiding the pantry by mid-afternoon. That matters for weight loss, because very restrictive eating often ends in exactly the overeating it was meant to prevent.

When meals feel balanced and complete, you're less likely to snack on empty calories, less likely to overeat at the next meal and more likely to stay with your plan.

The research backs a higher-fat, Mediterranean-style pattern, with the right caveats. The PREDIMED trial put 7,447 adults at high heart risk on a Mediterranean diet with extra-virgin olive oil, the same diet with nuts, or a lower-fat control diet. Over about 4.8 years, both higher-fat groups had roughly 30% fewer major cardiovascular events. It measured heart health, not weight, but it showed that adding healthy fat didn't backfire.

For weight, the MedWeight study followed 565 adults who had already lost at least 10% of their weight. Those in the top half for Mediterranean diet adherence had about twice the odds of keeping it off. It's an observational study, so it shows a link, not proof. The point holds: the goal isn't avoiding fat, it's choosing the right fats and using them on purpose.

For a complete overview of foods that support weight loss, including which fats made the list, see our 100 Best Foods for Weight Loss guide.

Best fats for weight loss

Not all fats are equal. Here's where to focus, ranked by the strength of the evidence and how easily each one replaces something less helpful, with links to our deeper guides where we have them.

Olive oil & other liquid plant oils

Cooking fat

About 120 calories per tablespoon · 10g monounsaturated fat

Extra-virgin olive oil is the gold standard. It's rich in monounsaturated fat and polyphenols that support heart health. In a 2025 survey of 16,273 adults in Frontiers in Nutrition, people who used it 6 or more days a week had a lower average BMI (24.7 vs 26.6) and a smaller waist (89 vs 99 cm) than people who used it less than 3 days a week. It was a one-time online survey, so it shows an association, not cause and effect. Use it for dressings, roasting vegetables and low-to-medium-heat cooking.

Canola, soybean and sunflower oils are good options too. The rule of thumb: choose liquid oils over solid fats like butter, shortening and coconut oil when you can. One tablespoon of olive oil has about 120 calories, per the USDA nutrient database, so measure it rather than pouring it freely.

Why it works: it replaces butter in cooking and creamy dressing on salads. Watch for: a long pour can add 300 calories before the food is even plated.

Nuts & nut butters

Most filling

About 165 to 185 calories per ounce · 190 calories in 2 tbsp peanut butter

This one surprises most people. Nuts are among the most calorie-dense foods there are, yet people who eat them regularly don't weigh more than people who avoid them, and often weigh less. A 2008 review in the Journal of Nutrition found that trials adding nuts for 1 to 6 months produced little or no weight change. The main reason is satiety. People eat less later, compensating for about 65 to 75% of the calories nuts provide.

Some of the fat isn't absorbed at all. A systematic review in Advances in Nutrition found that the energy you actually get from whole nuts is lower than labels predict, because some fat stays locked in the cell walls. And in a 2026 randomized trial in Obesity Research & Clinical Practice, 140 adults on a weight-loss diet ate almonds or carb-based snack bars. The almond group's hunger hormone, ghrelin, fell while the snack bar group's rose.

Portions still matter. In a study of 120 people asked to take a handful of nuts, the median handful was 36g, a bit over the 30g serving most guidelines use, and a "large handful" was about 61g. For the full science and practical tips, read our deep dive: Are Nuts Good for Weight Loss?

Nut butters deserve special attention because they're one of the easiest foods to overeat. Two tablespoons of peanut butter is about 190 calories, but most people eyeball closer to three or four tablespoons. Measure with a real tablespoon, not a spoon from the drawer. Our peanut butter guide covers portions, label reading and why peanut butter can help some people lose weight.

Why it works: protein, fat and fiber in one crunchy, filling package. Watch for: the jar has no portion control. Spoon it out, then put the jar away.

Avocados

Fat + fiber

160 calories & 7g fiber per 100g, about half an avocado

Avocados are creamy, versatile and packed with monounsaturated fat and fiber. About 100g, roughly half a medium avocado, has 160 calories and 7g of fiber, per USDA nutrient data, and enough fat to make a meal more satisfying.

They're not a weight loss food on their own, though. In the HAT trial in the Journal of the American Heart Association, 1,008 adults with a large waist added one large avocado a day for 6 months without changing anything else. Belly fat (measured by MRI) and body weight didn't change compared with their usual diet. The benefit comes from using avocado instead of mayo, cheese or butter on sandwiches and toast, not on top of them.

For portions and the research on avocados and weight, see Are Avocados Good for Weight Loss?

Why it works: it replaces higher-saturated-fat spreads and brings fiber with it. Watch for: a whole large avocado can top 300 calories.

Fatty fish

Omega-3s

34g protein in 6 oz raw wild salmon · 2 servings a week

Salmon, sardines, mackerel, trout and herring provide the omega-3 fats most people don't get enough of. The American Heart Association recommends two servings of fish a week, about 3.5 ounces cooked each, especially fatty fish.

For weight loss, fatty fish has another advantage: it's high in protein. A 6-ounce wild Atlantic salmon fillet, weighed raw, has about 34 grams of protein along with its healthy fat, which makes it one of the most satisfying dinners there is. Bake it, grill it or pan-sear it. Skip the deep fryer.

Why it works: protein and fat together keep you full for hours. Watch for: breaded and fried fish brings back the calories the fish saved you.

Chia, flax, hemp & pumpkin seeds

Omega-3 & fiber

138 calories & 10g fiber per ounce of chia seeds

Chia seeds, flaxseeds, hemp seeds and pumpkin seeds pack omega-3s (especially chia and flax), fiber and minerals into a small serving. An ounce of chia seeds has 138 calories and about 10g of fiber, per USDA data. A tablespoon of ground flaxseed is about 37 calories.

Sprinkle them on yogurt, blend them into smoothies or stir them into oatmeal.

Why it works: they add fiber and healthy fat to foods that would otherwise have neither. Watch for: seeds are as calorie-dense as nuts, so use a spoonful, not a handful.

Fats to limit for weight loss

Some fats work against both your waistline and your heart. These aren't never-eat foods, but they shouldn't be your defaults.

Saturated fats

Saturated fat from butter, lard, fatty cuts of meat and tropical oils like coconut and palm should be limited. The current Dietary Guidelines for Americans, 2025 to 2030, keep saturated fat under 10% of daily calories, about 22g on a 2,000-calorie day. They now list butter and beef tallow as cooking options too, but they still put olive oil first. That doesn't mean you can never cook with butter. Make olive oil your go-to.

Trans fats

Artificial trans fats from partially hydrogenated oils have been largely removed from the U.S. food supply. Still, check labels on older products and anything imported. If you see "partially hydrogenated" in the ingredients, skip it.

Unmeasured fats

These are the sneaky problem. A "drizzle" of olive oil can easily be 3 tablespoons, or 360 calories. Cooking with "a little butter" often means half a stick. Nut butter eaten straight from the jar has no portion control at all. The fats themselves aren't bad. Like most foods, they work in measured amounts.

How to use fat for weight loss

Fat has 9 calories per gram, compared with 4 for protein or carbs. That's why it's so satisfying, and why it's easy to overdo. Here's how to get the benefits without the excess.

Substitute, don't add. The biggest mistake with healthy fats is adding them on top of what you already eat. Avocado toast is great, if you're not also buttering the bread. Olive oil dressing works, if you're not also adding cheese and croutons. Think replacement, not accumulation.

Measure your oils and nut butters. This one habit can save hundreds of calories a day. Use measuring spoons, not your eyes. Once you've seen what a tablespoon actually looks like, you can relax a little, but most people are shocked by how much they've been using.

Pair fats with protein and fiber. Fat alone doesn't keep you as full as fat with protein and fiber. Salmon (fat and protein) with roasted vegetables (fiber) is a strong weight loss dinner. Avocado (fat) on whole-grain toast (fiber) with eggs (protein) covers all three. That's the same formula behind our Weight Loss Meal Plan: balanced macros in portions that are already measured.

Hit your targets. The Institute of Medicine's acceptable range for adults is 20 to 35% of calories from fat. Here's what that means in grams. Use a calorie calculator to set your baseline, then build meals that fit.

1,600: 20% of calories 36g · 35% of calories 62g
1,800: 20% of calories 40g · 35% of calories 70g
2,000: 20% of calories 44g · 35% of calories 78g

Healthy fats in Clean Eatz Kitchen meals

Every Clean Eatz Kitchen meal is chef-cooked and portion-controlled, so the measuring is done before it reaches you. We'd rather show you the fat numbers than promise they're all low.

On our current menu of 32 meals, fat runs from 4g to 28g a meal, with a median of 13.5g. Twenty-four of the 32 get 35% or less of their calories from fat. The leanest is Baja Salmon, our one salmon meal, at 250 calories, 4g of fat and 25g of protein. The eight that run higher, up to about 49% of calories from fat, are the comfort meals: Hashbrown Stack, Garlic Ranch Chicken Potato Skins, Adobo Steak Nachos and similar. Every number is on our Nutrition Info page.

If fat is the number you're watching, sort that table by fat, or start with Build A Meal Plan, which lets you pick meals one by one and filter by protein. Meals arrive frozen, keep up to 12 months and heat in a few minutes.

Best fats for weight loss bottom line

The right fats, olive oil, nuts, avocado, fatty fish and seeds, make meals satisfying and support long-term health. The key is using them to replace less helpful options, measuring portions and pairing them with protein and fiber.

For specific foods, explore our deep dives:

And for the complete picture of weight loss nutrition, see our 100 Best Foods for Weight Loss guide.

Sources

Frequently asked questions

Can eating fat help you lose weight?

Fat doesn't directly cause weight loss, but healthy fats help you stay full longer and make meals more satisfying. When unsaturated fats replace saturated fats or refined carbs, rather than being added on top, they support both weight management and heart health. The key is substitution, not addition, and keeping total calories in check.

How much fat should I eat per day to lose weight?

Most guidance puts fat at 20 to 35% of daily calories. On an 1,800-calorie weight loss diet, that's about 40 to 70g of fat a day, and on 2,000 calories about 44 to 78g. Favor unsaturated sources like olive oil, nuts, avocado and fatty fish, and keep saturated fat under 10% of calories.

Are nuts too high in calories for weight loss?

Not if you portion them. People who eat nuts regularly don't gain weight from them, partly because nuts are filling enough that people eat less later, offsetting about 65 to 75% of their calories, and partly because some nut fat isn't absorbed. Stick to about 1 ounce (a small handful) per serving. See Are Nuts Good for Weight Loss?

Is olive oil better than butter for weight loss?

For most people, yes, mostly for heart health. Olive oil is rich in monounsaturated fat, while butter is high in saturated fat, and both have about 100 to 120 calories per tablespoon. People who use extra-virgin olive oil daily tend to have smaller waists, though that evidence is observational. Use it instead of butter, not in addition.

What are the worst fats for weight loss?

Artificial trans fats from partially hydrogenated oils are the worst, mainly because of heart disease risk, and they've been largely removed from U.S. food. Limit saturated fat from butter, lard and tropical oils. The biggest practical problem is usually unmeasured fat: free-poured oil, nut butter from the jar and creamy dressings nobody counts.