Bo guide
Short answer
Set protein first at roughly 0.7–1g per pound of target body weight, set fat at about 25–35% of calories, and fill the remainder with carbohydrate. Protein is the target worth hitting precisely.
General information, not medical advice. Written from published sources, which are listed at the end. It is not a substitute for a doctor, pharmacist or registered dietitian who knows your situation.
In this guide8 sections · 3 min
Macros are the three things that carry calories: protein (4 cal/g), carbohydrate (4 cal/g) and fat (9 cal/g). Calories tell you how much energy; macros tell you what it is made of, and that changes body composition, hunger and training.
What each one is for
| Macro | Calories/g | Main job | How precise to be |
|---|---|---|---|
| Protein | 4 | Preserves and builds muscle; most filling | Hit it. Within 5–10 g. |
| Fat | 9 | Hormones, vitamin absorption, satiety | Keep above ~20% of calories. |
| Carbohydrate | 4 | Fuel, especially for hard training | The flexible remainder. |
| Alcohol | 7 | Nothing nutritional | Log it; it still counts. |
Setting your targets
- Start from calories. Macros have to add up to your calorie target, so set that first.
- Protein first. Roughly 0.7–1g per pound of target body weight. This is the one that protects muscle in a deficit and keeps you full.
- Fat next. About 25–35% of total calories. Going much lower is unpleasant and unnecessary.
- Carbs get the rest. They are the flexible one — fuel for training and, for most people, the easiest lever to move.
A worked example
An 80 kg person eating 2,000 calories in a deficit:
- Protein at 1.8 g/kg = 144 g → 576 calories.
- Fat at 30% of 2,000 = 600 calories → 67 g.
- Carbohydrate gets what is left: 2,000 − 576 − 600 = 824 calories → 206 g.
So: 144 g protein, 67 g fat, 206 g carbs. Change the calorie target and only the carbohydrate number needs recalculating — protein stays anchored to body weight, and fat has a floor rather than a formula.
Tracking without it eating your life
- Log before you eat, not after. Easier to adjust a meal than regret it.
- Build a rotation. Most people eat the same 20 or so meals. Log them once and reuse.
- Weigh the calorie-dense things. Oil, nut butter, cheese, nuts. Vegetables can be eyeballed; olive oil cannot.
- Aim for close, not exact. Within 5–10g on protein and calories is plenty. Precision beyond that buys nothing.
What 30 g of protein actually looks like
The target is meaningless without a sense of portions. Roughly 30 g of protein is:
| Food | Amount | Protein |
|---|---|---|
| Chicken breast, cooked | 110 g | ~33 g |
| Greek yoghurt, 0% | 280 g | ~30 g |
| Eggs | 5 large | ~31 g |
| Tinned tuna | 1.5 tins | ~30 g |
| Cottage cheese | 250 g | ~30 g |
| Firm tofu | 340 g | ~30 g |
| Lentils, cooked | 330 g | ~30 g |
Two things jump out. Animal sources hit the target in a portion you would eat anyway; plant sources need noticeably larger portions, which is the real reason plant-based diets under-deliver on protein rather than any quality argument. And five eggs is a lot of eggs — if breakfast is your weak meal, yoghurt or cottage cheese does the job with less effort.
The mistakes that make tracking useless
- Trusting database entries. Crowd-sourced entries in most apps are frequently wrong. Prefer verified or own-brand entries, and be suspicious of anything suspiciously round.
- Logging raw weights and eating cooked, or the reverse. 100 g of raw chicken is not 100 g of cooked chicken. Pick one and be consistent.
- Forgetting liquid calories. Juice, lattes, cooking wine and beer are the classic invisible surplus.
- Ignoring the weekend. Five tracked days and two untracked can wipe out the entire week — the most common reason a deficit does not show up.
Fibre deserves a look too
Not a macro in the strict sense, but worth a target. Most adults fall well short of the roughly 30 g a day recommended, and fibre does a disproportionate amount for fullness per calorie — which makes it one of the cheapest ways to make a deficit tolerable.
Practically: if your carbohydrates come mostly from whole grains, legumes, fruit and vegetables rather than refined sources, you will hit it without tracking it separately.
How long should you track?
Long enough to calibrate your eye — usually four to eight weeks. Most people find that after a couple of months they can estimate well without logging every meal, and only return to tracking when they want to change something.
Tracking is a measuring tool, not a permanent lifestyle. If it starts feeling compulsive rather than useful, that is a good reason to stop and talk to someone.
