Fats and sugars, without the folklore

Which fat and which sugar actually matter, why swapping one sweetener for another changes almost nothing, and what the numbers on a nutrition breakdown are really telling you about both.

Published 2 August 2026 · updated 2 August 2026

Fat and sugar attract more confident bad advice than the rest of nutrition put together. Almost all of it comes from treating each as one substance. They are not: the useful questions are which fat and which sugar, and the answers point in opposite directions.

Every figure below is per 100 g from USDA FoodData Central — the same data the calculator uses, so you can paste a recipe and check any of it.

Fat: the type is the decision, the amount rarely is

All fat is 9 kcal per gram. Butter, olive oil and lard are within 20% of each other on calories, and no swap between them will meaningfully change what a recipe costs you in energy.

What does change is the mix of fatty acids, and the spread there is enormous:

Coconut oil carries eleven times the saturated fat of rapeseed oil at the same calories. That is the whole argument, and it is why the calculator’s fat goal is labelled Cut saturated fat rather than “cut fat”: cutting the amount changes a number, changing the type changes the number that has a Daily Value attached to it (20 g, and 100 g of butter is two and a half days of it).

What “saturated” is doing

Saturated fat raises blood LDL; unsaturated fats generally lower it. That is the mechanism behind every mainstream guideline on the subject, and it is why saturated fat is the only fat type on a nutrition label with a limit beside it.

Two things that follow, and often surprise people:

• Coconut oil is not a health fat. It is the most saturated fat in an ordinary kitchen — more than butter, more than lard. Whatever else is true of it, it is not a way to reduce saturated fat.
• Animal versus plant is the wrong axis. Lard is less saturated than butter and much less than coconut oil. Olive oil and rapeseed oil are the outliers because of their fatty acid profile, not their origin.

The fats worth eating more of, not less

The omega-3 and omega-6 rows in a breakdown are polyunsaturated fats your body cannot make. Oily fish is where omega-3 arrives in a form that needs no conversion — salmon is 3.9 g of polyunsaturated fat per 100 g, a large part of it EPA and DHA. Walnuts, flaxseed and rapeseed oil carry the plant form, ALA, which converts inefficiently but still counts.

A breakdown showing a dash rather than a figure on these rows means no ingredient in your recipe had a value recorded for them — not that there is none. It is the one place the site will not fill a gap with a zero.

Sugar: the split is added versus intrinsic

There is one number on a label with a limit beside it, and it is not total sugars. It is added sugars: 50 g Daily Value, and the FDA definition is about where the sugar came from, not what it is.

Sucrose from a bag and sucrose from an apple are the same molecule. The difference is everything arriving with it. So:

A glass of milk and a spoon of honey both put sugar in a breakdown; only one of them counts against the 50 g. This is not a loophole — it is the whole point of the distinction, and it is why a recipe full of fruit can show high total sugars and still be fine.

Sweetener swaps are mostly lateral

The single most common substitution people ask about — sugar for honey, or maple syrup, or agave — moves almost nothing. Per 100 g honey is 304 kcal against sugar’s 387, maple syrup 260, agave 310. Weight for weight you save between a fifth and a third of the calories, all of the sugar still counts as added, and the liquid sweeteners bring water that changes the recipe.

The mineral content people cite for molasses and dark syrups is real and, at recipe quantities, negligible: you are not going to meet an iron requirement out of a tablespoon of anything sweet.

The change that works is using less. Most baking tolerates a quarter less sugar with nobody noticing — that is a real 25% cut against a 50 g limit, and it is available in every recipe. The swaps guide goes through what sugar is doing structurally before you take it out, which matters in some recipes and not at all in others.

Sugar alcohols and the zero-calorie sweeteners

Erythritol and stevia are 0 kcal and contribute no sugars in the table this site uses. They work in things where sugar is only sweetening — a drink, a sauce, a custard. They do not work where sugar is doing structural work: caramelisation, browning, keeping a cake moist, giving a meringue something to hold.

What to actually look at

In a breakdown of your own recipe, in this order:

1. Saturated fat, per serving, against the 20 g limit. If it is high, look at which row is responsible — the calculator names it — and consider a swap of type.
2. Added sugars against 50 g. Total sugars without added sugars beside it is not a number you can act on.
3. The fat split. A recipe where most of the fat is monounsaturated is in a different position from one where most of it is saturated, at identical total fat.

Everything above is per serving, and the serving count is a setting you can change — halve it and every figure doubles.

The companion guide, reading a nutrition breakdown, covers the rest of the panel: protein, fibre, sodium and the micronutrients.

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