How many calories and macros should I eat?

Start from your TDEE — your BMR multiplied by an activity factor between 1.2 and 1.9. To lose fat, take about 20% off it. To maintain, eat it. To gain lean mass, add about 12%. For most adults that lands somewhere between 1,600 and 3,000 kcal, but the honest answer is the number that moves your weight the way you want over three weeks.

BMR is what you would burn lying still all day — usually 60 to 70% of the total. TDEE is BMR multiplied by an activity factor and is what you actually burn. Diet targets are set from TDEE, never from BMR: eating at your BMR is a severe deficit, not maintenance.

Mifflin-St Jeor (1990) is the better one for most people; Frankenfield’s 2005 review found it the most accurate of the common equations in non-obese and obese adults alike. The revised Harris-Benedict (1984) tends to read a little higher. This hub shows both and lets you pick which drives the target, because the gap between them is usually under 100 kcal.

For anyone training, roughly 0.7 to 1.0 g per pound of bodyweight per day — about 1.6 to 2.2 g per kilogram. Go towards the top of that range when you are in a deficit, because protein is what stops the weight you lose from being muscle. Above about 1 g per pound the extra buys you very little.

Set protein by bodyweight first, then fat as a percentage of calories with a floor around 40 g a day, and let carbohydrate take whatever is left. The common flexible starting split is 30% protein, 30% fat and 40% carbohydrate. Endurance training pushes carbs up; DASH sets 55% carbs and 18% protein deliberately.

About 20% below maintenance, which for most people is 400 to 600 kcal and produces 1 to 1.5 lb of loss a week. Bigger deficits do not speed fat loss proportionally — they increase the share of the loss that comes from muscle, and they are harder to sustain long enough to matter.

Not on its own. Trials that match 16:8 against normal eating at the same calories and protein find the same fat loss. What fasting does is make a deficit easier to hold for some people by removing decisions. The practical downside is that an 8-hour window makes a high protein target harder to hit.

By phase: 20 g of net carbohydrate a day during induction, then 40 g in active weight loss, 65 g in pre-maintenance and 90 g in maintenance. Induction is designed for about two weeks. At 20 g a day, hitting the fibre recommendation takes deliberate planning.

The standard DASH plan caps sodium at 2,300 mg a day — about 5.75 g of salt. The strict arm caps it at 1,500 mg, about 3.75 g of salt, and that arm produced the biggest blood-pressure reductions in the DASH-Sodium trial. A typical Western diet runs near 3,400 mg, and most of it comes from processed food rather than the salt shaker.

Glycemic index rates how fast a food raises blood glucose relative to pure glucose, regardless of how much you eat. Glycemic load adjusts for the portion: GL = GI × available carbs ÷ 100. Watermelon has a high GI of about 72 but a GL under 5 per serving, because a slice barely contains any carbohydrate. Under 10 is low, 10 to 19 medium, 20 and over high.

The IOM adequate intakes are 38 g a day for men aged 19 to 50 and 30 g from 51, and 25 g for women aged 19 to 50 and 21 g from 51. Pregnancy is 28 g and lactation 29 g. Most adults get about half of that, and the gap is the single easiest nutrition fix available.

Ethanol carries 7 kcal per gram, which is closer to fat than to sugar, and it comes with residual carbohydrate depending on the drink. A 12 oz regular beer runs about 150 kcal, a 5 oz glass of dry wine about 120, and a 1.5 oz shot of a 40% spirit about 97. Alcohol calories sit on top of your target, not inside it, unless you plan for them.