Guide
How the macro calculator works
Four steps, worked through for the example: a 38-year-old woman, 5 ft 5 in and 172 lb, who exercises 1 to 3 days a week at a moderate pace and wants to lose 1 lb a week.
1. Your resting burn
We start with the calories your body burns at rest, using the Mifflin-St Jeor equation. It is the same engine as the weight loss calculator by date, so you get the same calories in both. If you add your body fat %, we switch to Katch-McArdle, which works from your lean mass. Find it with the body fat calculator.
Women10 × kg + 6.25 × cm − 5 × age − 161
Example1,460 calories a day at rest
2. Your activity factor
Your daily movement sets the base: 1.2 if you rarely move, up to 1.5 if you move all day. Each exercise session adds a little on top, more for harder sessions. Walking more is the easiest way to raise your base; the walking weight loss calculator shows how many steps it takes.
Factordaily movement + sessions a week × value per session
Example1.3 + 2 × 0.0375 = 1.375, so a daily burn of 2,010 calories
3. Your calorie target
To lose weight, we take 500 calories a day off your daily burn for each pound a week. To lose fat and build muscle, we take 250. To build muscle, we add 250. Your target never goes under 1,200 calories for women or 1,500 for men.
Lose weightdaily burn − 500 × lb a week
Example2,010 − 500 = 1,510 calories a day
4. Protein first, then fat, then carbs
Protein is set in grams per kg of body weight, not as a share of calories. A fixed share gives a smaller person too little protein and a larger person too much. Fat takes 30% of calories, and carbs fill the rest. At a BMI of 30 or more, protein uses your weight at a BMI of 25, so the target stays realistic.
Protein1.6 g × kg (4 calories a gram)
Fat30% of calories ÷ 9
Carbswhat is left ÷ 4
Example125 g protein, 50 g fat, 140 g carbs
These numbers are estimates. Track your weight for 2 to 3 weeks, and recalculate after every 5% you lose.
Protein, carb and fat ratios for weight loss
The Dietary Guidelines for Americans give healthy ranges for adults: protein 10 to 35% of calories, carbs 45 to 65% and fat 20 to 35%. In a calorie deficit we put protein near the top of its range on purpose, because it helps you keep muscle and stay full. That is how much protein you need to lose fat rather than muscle.
| Style | Protein | Carbs | Fat | Best for |
|---|---|---|---|---|
| Balanced Default | 125 g | 140 g | 50 g | Most people |
| High protein | 155 g | 110 g | 50 g | Keeping muscle, staying full |
| Lower carb | 125 g | 105 g | 65 g | People who feel better with fewer carbs |
Lower carb is not better for fat loss when calories and protein match. Pick the style you can keep. Custom lets you set your own split, and its sliders stop at the safe floors.
Lose fat and build muscle at the same time
Losing fat while you gain muscle works best for beginners, people coming back to training, and people with more body fat. It takes three levers:
A small deficit. About 250 calories a day under your daily burn, so you still have energy to train.
Protein around 2.0 g per kg. For the example, that is 155 g a day. The protein calculator breaks it down meal by meal.
Strength training 2 or more days a week. The Physical Activity Guidelines for Americans advise it for every adult.
The scale can stall while fat falls and muscle grows, so track your body fat, not just your weight.
When your macros need adjusting
No change after 2 to 3 weeks
Check how accurately you log first. Then lower calories by 100 to 200, never below the floor.
Always hungry
Move calories toward protein and fibre. Both keep you full for longer.
Low energy in training
Move calories toward carbs, and eat them around your workouts.
The target looks too low
Pick a slower pace. Half a pound a week still adds up.
When hunger beats the plan
Macros only work if you can eat to them. When hunger and cravings keep pushing you past your targets, GLP-1 treatment works on appetite itself.
GLP-1 medicines slow how fast your stomach empties and act on appetite centers in the brain, so you feel full sooner and think about food less.
- 14.9%
- Average weight loss at 68 weeks on semaglutide 2.4 mg. STEP 1, Wilding et al., NEJM 2021.
- 20.9%
- Average weight loss at 72 weeks on tirzepatide 15 mg. SURMOUNT-1, Jastreboff et al., NEJM 2022.
Both trials paired the medicine with diet and activity changes. Results vary.
Habits first. A clinical push when your body needs it. A licensed clinician decides if treatment is right for you.
Compounded medications are tailored to a patient's needs and are not reviewed or approved by the FDA for safety or effectiveness. Prescription required. Eligibility, prescribing, and dosing are determined individually by a licensed clinician based on your medical history. Treatment is not appropriate for everyone. Results vary.