How to set up your diet for your goals
Your training decides the stimulus; your diet decides what your body does with it. Whether you want to lose fat, build muscle or hold steady, it comes down to one lever — how much energy you eat relative to how much you burn — plus enough protein to protect or build muscle. Everything else is detail on top of those two things.
This guide walks through choosing a goal, setting a sensible starting point, and — the part that actually matters — adjusting based on what really happens over a few weeks rather than trusting any calculator to be perfect. It pairs with our calorie calculator, which gives you the starting numbers.
Pick one direction at a time
You can lose fat, or build muscle at your best rate, or maintain — but you can only fully prioritise one at a time, because losing fat needs an energy deficit and building muscle is best served by an energy surplus. Trying to do both at once (the eternal 'recomp' dream) is possible for beginners and people returning from a break, but it's slow, and for everyone else it means doing both jobs at half speed.
So choose a direction and commit to it for a block of months, not days. A common sensible pattern: if you're carrying more fat than you'd like, run a fat-loss phase first to get lean, then switch to a muscle-building phase. If you're already lean, start by building. Chasing the goal you happen to feel like each week is how people spend a year going nowhere.
Setting your calories
Start from your maintenance level — the calories that keep your weight stable — which our calorie calculator estimates from your body stats and activity. To lose fat, eat below it: a deficit of around 15-20% (very roughly 300-500 calories a day for many people) drives steady fat loss of about 0.5-1% of bodyweight per week, which is sustainable and muscle-sparing. To build muscle, eat slightly above maintenance: a small surplus of around 10% (a few hundred calories) supports growth without piling on excess fat. To maintain, eat around maintenance and let performance guide small tweaks.
Resist the urge to be aggressive. A brutal deficit costs you muscle, energy and adherence; a huge surplus just adds fat you'll have to lose later. Slower is genuinely faster here, because a moderate plan you can sustain for months beats an extreme one you quit in two weeks — which describes most failed diets.
Every calorie number from any calculator is an estimate, and individual metabolism varies by 10-20%. Treat your starting figure as a hypothesis to test over three to four weeks, not a fact.
Protein first, then the rest
Once calories are set, protein is the macronutrient to lock in: aim for roughly 1.6-2.2 g per kg of bodyweight per day, leaning higher when you're in a deficit to protect muscle. It's also the most filling nutrient, which makes a diet far easier to stick to. After protein, the split between carbs and fats is largely down to preference and performance — there's no magic ratio. Keep fats high enough for health (a common floor is around 0.5-0.8 g/kg) and fill the rest of your calories with carbohydrates, which fuel hard training.
That's the whole framework: hit your calorie target, hit your protein, keep fats reasonable, and let carbs make up the balance. Chasing precise macro percentages beyond this adds effort without adding results for almost everyone.
Adjust by what actually happens
This is the step that separates people who progress from people who spin their wheels. Set your numbers, then track two things for three to four weeks: your bodyweight (a weekly average, since daily weight swings with water and food) and roughly how you're eating. Then read the trend. Losing weight too fast, or feeling wrecked? Add a little food. Not losing at all on a fat-loss phase? Your real maintenance is lower than estimated — trim slightly. Gaining fat quickly on a muscle phase? Ease the surplus back.
The calculator gives you a starting point; your own results over a month give you the truth. Adjust in small steps, give each change a few weeks to show, and you'll converge on numbers that actually fit your body. That feedback loop — set, measure, adjust — is the entire skill of diet, and it's far more reliable than any formula.
DropSet syncs your daily calories and protein from Apple Health or Health Connect — logged in whatever food app you use — and shows them alongside your body-weight trend and training, so the feedback you need to judge your plan sits in one place.
Common questions
How many calories should I eat to lose fat?
Start about 15-20% below your maintenance calories — very roughly 300-500 fewer per day for many people — which drives steady fat loss of around 0.5-1% of bodyweight a week. Estimate maintenance with a calorie calculator, then adjust based on your actual results over a few weeks.
How many calories to build muscle?
A small surplus of around 10% above maintenance — a few hundred extra calories a day — supports muscle growth without adding much fat. Bigger surpluses just add fat you'll have to lose later; muscle can only be built so fast.
Can I build muscle and lose fat at the same time?
Beginners and people returning after a break often can, slowly. For most trained people it's more effective to pick one goal at a time — a fat-loss phase or a muscle-building phase — since the two pull calories in opposite directions.
What macros should I eat?
Set protein first (about 1.6-2.2 g/kg of bodyweight), keep fats high enough for health (roughly 0.5-0.8 g/kg minimum), and fill the rest with carbs to fuel training. Beyond that, exact carb-to-fat ratios are down to preference — there's no magic split.
Are calorie calculators accurate?
They give a good starting estimate, but individual metabolism varies by 10-20%, so no calculator is exact for you. Use the number as a hypothesis, track your weight trend for three to four weeks, and adjust up or down based on what actually happens.
Put it into practice
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