Work out how many grams of fat and saturated fat fit in your day for maintaining, losing or gaining weight.
Dietary guidelines for adults suggest getting 20% to 35% of daily calories from fat. Fat holds more energy than the other nutrients, about 9 calories a gram on food labels, so a small amount of fat covers a large share of calories. The calculator uses 8.8 calories per gram and works out the grams from your daily calorie needs for your chosen goal.
Saturated fat is the type found mostly in butter, cheese, fatty meat and some oils such as coconut and palm oil. Health authorities advise keeping it to less than 10% of daily calories, and to about 7% for people who want to lower their risk of heart disease. The table shows both limits in grams. Replacing some saturated fat with unsaturated fat from fish, nuts, seeds and olive oil is generally better for your heart.
Your calorie needs come from your basal metabolic rate, found with the Mifflin-St Jeor formula or the Katch-McArdle formula if you know your body fat, multiplied by an activity factor. Eating about 500 calories a day less leads to a loss of about 1 pound, or half a kilogram, a week, and eating 500 more leads to a gain. The fat allowance moves up or down with the calories for each goal.
Most guidelines suggest 20% to 35% of your daily calories. On 2,000 calories a day, that is about 45 to 80 grams of fat.
Food labels use 9 calories per gram. This calculator uses 8.8 calories per gram, which is a common figure for mixed dietary fat.
Less than 10% of daily calories is the usual limit, and about 7% is advised for people trying to reduce heart disease risk.
Weight change depends on total calories. Fat is calorie dense, so it is easy to eat a lot of calories from it, but what matters most is whether you eat more or less than you burn.
A very large calorie deficit can take your target below zero. That is not a real or safe goal, so treat those rows as a sign the deficit is too big.
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