Nutrition Basics 101: Fat

In our last post we explained why we want Nutriely to help you learn about nutrition, not just track it. So it's only fair that we start teaching. And what better place to start than the basics. This is the first post in our Nutrition Basics 101 series, and today's topic is fat.

Fat is a very misunderstood nutrient. Some people fear it, while others believe certain fats to be "superfoods". The truth, as always, lies somewhere in the middle.

In this post we'll cover the essentials everyone should know about dietary fat.

What is fat?

Fat is one of the macronutrients, alongside carbohydrates and protein, which provide us with energy. Macronutrients are nutrients our bodies need in relatively large amounts. Fat is the most energy-dense of them: it provides 9 calories (kcal) per gram, while carbohydrates and protein provide only 4 kcal per gram.

Dietary fat can be divided into two main groups:

Saturated fat
Unsaturated fat, which can be further divided into:
- Monounsaturated fat
- Polyunsaturated fat

The difference between these types is the number of double bonds in the fatty acid molecule. But you don't need to remember the chemistry behind the names. The most important thing to know is that fats are not all the same, and different types affect our health differently.

Most foods contain both saturated and unsaturated fats, but in different proportions. Depending on which type a food has the most of, it's considered a source of either unsaturated or saturated fat.

Unsaturated fat

Unsaturated fats are generally considered the healthier type of fat, and they should make up most of the fat in your diet.

They are usually liquid at room temperature, and are found in foods such as:

Nuts
Seeds
Avocados
Olive oil
Canola (rapeseed) oil
Sunflower oil

For the full lists, see the foods highest in monounsaturated fat and polyunsaturated fat.

Some unsaturated fats are what we call essential fatty acids. "Essential" means your body cannot produce them, so you must get them from food. The two essential fatty acids are linoleic acid (an omega-6 fatty acid) and alpha-linolenic acid (an omega-3 fatty acid).

Good sources of essential fatty acids are:

Nuts, for example walnuts, pecans and pistachios
Seeds, for example sunflower, sesame, pumpkin, chia, flax and hemp seeds
Plant oils, like sunflower, soybean, canola and flaxseed oil

There are other omega-3 fatty acids you might have heard of: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These are long-chain omega-3s. Technically your body can make them from alpha-linolenic acid, but the conversion rate is rather small. That's why it's often suggested to get EPA and DHA directly from your diet by eating seafood, or to take a supplement (fish oil, or algae oil as a vegan option).

Saturated fat

Saturated fats, on the other hand, are usually solid at room temperature.

Common foods high in saturated fat include:

Butter
Cheese
Fatty cuts of meat
Lard
Coconut oil
Palm oil
Cocoa butter

You can see the full list of foods highest in saturated fat in our catalog.

Many health organisations recommend keeping saturated fat under 10% of your daily energy intake, because eating large amounts over time can increase the risk of cardiovascular disease [1] [2]. One reason is that saturated fat tends to raise LDL cholesterol (often called the "bad" cholesterol), which contributes to atherosclerosis: the build-up of plaque in the arteries.

This doesn't mean you have to avoid foods containing saturated fat completely. Instead, be mindful of the high-saturated-fat foods you eat, and try to make unsaturated fats the main source of fat in your diet.

How much is 10%?

First, you need an estimate of how many calories you need per day. You can use our daily requirement calculator or any other calorie calculator. Then multiply that number by 0.1 (10% of your energy) and divide by 9 (the calories in 1 g of fat).

For example, someone who needs 2,000 kcal a day should aim to keep saturated fat under about 22 g per day (2,000 × 0.1 ÷ 9 ≈ 22).

What about trans fat?

There's one more type of fat we haven't mentioned yet: trans fat. This one should be kept as low as possible.

Technically, trans fats are unsaturated fats where the double bond is in a "trans" arrangement. Again, chemistry you don't need to remember. What you should know is where trans fats come from.

Small amounts of trans fats are made naturally by ruminant animals (like cows and sheep), so they can be found in meat and dairy products. But most of the trans fat in people's diets usually comes from processed foods. Trans fats are mainly created during a manufacturing process called partial hydrogenation, which turns liquid oils (unsaturated fats) into more solid fats.

When hydrogenation is complete, nearly all unsaturated fat becomes saturated fat, and little to no trans fat is created. It's when the process happens only partially that trans fats appear. That's why it's a good idea to check ingredient lists and limit products containing partially hydrogenated oils.

Fully hydrogenated oils contain little to no trans fat, but they may still be worth limiting, because they are often high in saturated fat.

Foods that might contain trans fats include:

Commercial baked goods, such as cookies, cakes and donuts
Some fried foods
Some highly processed snacks

You can see which foods in our catalog have the most of it on our trans fat page.

The closer your trans fat intake is to zero, the better, because trans fat also increases your risk of cardiovascular disease [2].

Why do we even need fat?

Fat is essential for good health. Severely restricting it is not a good idea, because fat has many important jobs in the body.

You need fat to:

Provide your body with energy
Build and maintain cell membranes
Absorb fat-soluble vitamins (A, D, E and K) and other fat-soluble nutrients
Produce hormones (like testosterone, estrogen and others)
Support normal brain and nervous system function (a large part of your brain is made of fat)
Protect and cushion organs (for example, your kidneys are protected and held in place by a layer of fat)

Without enough fat in your diet, many of these processes can't work properly.

How much fat do we need?

Recommendations differ a little depending on who you ask. The Nordic Nutrition Recommendations suggest getting 25–40% of your daily energy from fat [3], the European Food Safety Authority recommends 20–35% [4], and the World Health Organization suggests keeping it at 30% or less [5]. For someone eating 2,000 kcal per day, that's roughly 44–89 g of fat.

Try to get most of your fat from unsaturated sources while limiting saturated fat. A few ways to do that:

Choose plant oils for cooking instead of butter, lard or coconut oil.
Eat nuts and seeds regularly.
If you eat meat, choose leaner cuts more often.

Every other nutrient has a list like the ones above too. You'll find them all in our nutrient catalog.

Key takeaways

Fat is an essential nutrient, necessary for good health.
Most of the fat in your diet should come from unsaturated sources, such as plant oils, nuts, seeds and avocados.
Get long-chain omega-3 fatty acids regularly, either from seafood or a supplement.
Eat saturated fat in moderation.
Avoid trans fat as much as possible.

Sources

Lichtenstein, A. H., Khera, A., Anderson, C. A. M., Appel, L. J., DeSilva, D. M., Gardner, C., Hu, F. B., Jones, D. W., Petersen, K. S., on behalf of the American Heart Association (2026). 2026 Dietary Guidance to Improve Cardiovascular Health: A Scientific Statement From the American Heart Association. Circulation, 153(18), e1285–e1295. https://doi.org/10.1161/CIR.0000000000001435
World Health Organization (2023). Saturated fatty acid and trans-fatty acid intake for adults and children: WHO guideline. https://www.who.int/publications/i/item/9789240073630
Blomhoff, R., Andersen, R., Arnesen, E. K., et al. (2023). Nordic Nutrition Recommendations 2023. Nordic Council of Ministers. https://doi.org/10.6027/nord2023-003
European Food Safety Authority (2017). Dietary Reference Values for nutrients: Summary report. EFSA Supporting Publications, e15121. https://doi.org/10.2903/sp.efsa.2017.e15121
World Health Organization (2023). Total fat intake for the prevention of unhealthy weight gain in adults and children: WHO guideline. https://www.who.int/publications/i/item/9789240073654