What fat actually does
Beyond being fuel, fat is infrastructure: sex and steroid hormones are built from it, every cell membrane contains it, and vitamins A, D, E, and K can't be absorbed without it. It also makes food taste like food — an underrated factor in whether a diet survives contact with real life.
The mistake worth avoiding
When calories get cut, fat is the tempting place to take them from — at 9 kcal per gram, it buys the most budget back. Cut it too far for too long, though, and the costs show up where people don't connect them: hormone levels, energy, mood, skin, cycle regularity. That's why your plan enforces a fat minimum scaled to your body, whatever diet style you pick — some calories are load-bearing.
Types, briefly
- Unsaturated fats (olive oil, nuts, avocado, fish) — the bulk of your intake, ideally; fish brings the omega-3s most diets run low on.
- Saturated fats (butter, fatty meat, coconut) — fine in moderation, worth keeping an eye on rather than eliminating.
- Trans fats (industrial partially-hydrogenated oils) — the one category worth actively avoiding.
The app tracks the breakdown where labels provide it — see micronutrients and nutrient goals for setting a ceiling on saturated fat if that's a number you manage.
Practical bar
Keep fat at or above your plan's floor, source most of it from unsaturated foods, and spend the rest of your calorie budget where it serves your training and appetite best.