How Much Fat Do You Need Per Day? A Practical Guide

TL;DR

• Set fat between 0.6 and 1.0 g/kg of bodyweight as a sensible working range for most people.
• Don’t drop below roughly 0.5 g/kg for long: very low fat can blunt testosterone and vitamin absorption.
• Fat carries 9 kcal per gram, more than double protein and carbs, so small tracking errors move your total fast.
• Fat type matters for health markers, but for weight change it’s total calories that decide the outcome.
• Once protein and fat have their floors, carbs fill whatever calories are left.

Protein gets the headlines and carbs get the arguments. Fat mostly gets ignored, or feared. That’s a mistake. Dietary fat isn’t just padding on your macro sheet; it’s the raw material for your sex hormones, the carrier for fat-soluble vitamins, and often the difference between a diet you can stick to and one that makes you miserable. So let’s put an actual number on it.

Why fat is not optional

You can survive on very little dietary fat, but “survive” and “function well” are different things.

Fat does three jobs you can’t easily replace:

Hormone production

Cholesterol and dietary fat are precursors to steroid hormones, including testosterone and oestrogen. Studies on low-fat diets in men have shown reduced testosterone when fat drops too low, particularly below around 20% of total calories. You don’t need to eat a stick of butter, but chronically starving fat is a bad trade.

Vitamin absorption

Vitamins A, D, E and K are fat-soluble. Eat your spinach with zero fat and you absorb far less of what’s in it. A little olive oil or a handful of nuts alongside vegetables meaningfully improves uptake.

Satiety and sanity

Fat slows gastric emptying and adds flavour and texture. A dinner with some fat in it feels like a meal. A dinner scrubbed of all fat feels like punishment, and punishment diets don’t last. If you’ve ever found yourself ravenous a couple of hours after a “healthy” low-fat meal, this is a big part of why you’re always hungry in a calorie deficit: fat is doing satiety work that a low-fat plate simply isn’t.

The working range: 0.6 to 1.0 g/kg

Here’s the practical target. Set fat between 0.6 and 1.0 g per kilogram of bodyweight per day.

For an 80 kg person, that’s roughly 48 to 80 g of fat daily. At 9 kcal per gram, that’s 432 to 720 kcal from fat, a chunk of your total that you’re deciding on before you touch carbs.

Where you land in that range depends on preference:

• Lower end (0.6 g/kg): more room for carbs, which helps if you train hard or just enjoy eating rice and bread.
• Higher end (1.0 g/kg): more satiety per meal, useful if you find high-carb days leave you hungry, or if you lean towards lower-carb eating. If that’s your preference, our keto macros guide covers how far you can push fat when carbs are deliberately minimal.

Neither is “better” in a vacuum. The best split is the one you can repeat.

The floor you shouldn’t cross

Don’t sit below about 0.5 g/kg for extended periods. Short dips are fine, nobody’s hormones collapse because of one low-fat day, but weeks of near-zero fat is where you start risking hormone and absorption problems. If a diet plan has you eating 20 g of fat a day for a month, that’s a red flag, not a virtue.

Fat is calorie-dense, so track it carefully

This is the operational reality most people miss: fat carries 9 kcal per gram, against 4 for both protein and carbs.

That density cuts two ways.

A tablespoon of olive oil is about 120 kcal. Eyeball it generously while cooking and you can add 200 to 300 unlogged calories to a “healthy” meal without noticing. Nut butters, cheese, oils and dressings are the classic culprits, calorie-dense, easy to under-measure, easy to over-serve. Untracked calories like these are usually the hidden reason someone stalls despite feeling like they’re eating carefully, the same trap covered in why the scale goes up in a calorie deficit.

The fix is boring but effective: weigh oils, nuts and nut butters rather than estimating. A food scanner gets you close on whole foods, but added fats are exactly where a scale earns its place. If you track with Chowdown, log the oil you cook in, not just the ingredients that go on the plate.

Does the type of fat matter?

For body weight, no. A calorie of saturated fat and a calorie of unsaturated fat move the scale identically. If your only goal is fat loss or gain, don’t overthink the source, and the same calorie deficit logic applies regardless of which fats you pick.

For long-term health markers, yes, it matters.

The rough hierarchy

• Prioritise: mono- and polyunsaturated fats. Olive oil, avocado, nuts, seeds, oily fish. Omega-3s from fish are worth deliberately including.
• Moderate: saturated fat. Butter, fatty meat, full-fat dairy, coconut oil. Fine in normal amounts; most guidelines suggest keeping it under roughly 10% of total calories.
• Minimise: industrial trans fats. Largely phased out of the food supply now, but worth avoiding where they linger.

You don’t need to hit these ratios to the decimal. Aim for the bulk of your fat coming from unsaturated sources, let saturated fat sit in the background, and you’ve done the important part.

Putting it in your macro plan

The clean order of operations:

1. Set protein first. Aim for 1.6 to 2.2 g/kg if you’re active or dieting; see how much protein you actually need for the full breakdown.
2. Set fat next. Pick your point in the 0.6 to 1.0 g/kg range.
3. Fill the rest with carbs. Whatever calories remain after protein and fat go to carbohydrate.

This is the same hierarchy we use across the best macro split for fat loss, and it only works once you know your total calorie target, which starts with calculating your TDEE.

Worked example, 80 kg person eating 2,200 kcal:

• Protein at 1.8 g/kg: 144 g, so 576 kcal.
• Fat at 0.8 g/kg: 64 g, so 576 kcal.
• Remaining: 1,048 kcal, so about 262 g of carbs.

That’s a balanced, sustainable split with hormones and satiety looked after, and plenty of carbs to fuel training.

The takeaway is simple. Give fat a floor, give it a ceiling, weigh the sneaky calorie-dense sources, and stop treating it as the macro to fear. It’s doing more work than you give it credit for.