How Many Calories Should I Eat?

The standard figures you'll see are 2,000 calories a day for women and 2,500 for men. These come from the Scientific Advisory Committee on Nutrition (SACN) and are based on averages across the adult population. They're a reasonable starting point, but they're not personalised.

Your actual calorie needs depend on your age, height, weight, body composition, and how physically active you are. A 25-year-old who runs five times a week needs considerably more calories than a 65-year-old with a desk job. The "right" number of calories is the amount that maintains a healthy weight for your frame, gives you enough energy to function, and doesn't leave you hungry all the time.

What the guidelines actually say

SACN publishes estimated average requirements (EARs) for energy. These are population averages, not individual targets. For adults aged 19-64 with a typical activity level:

• Women: approximately 2,000 kcal/day
• Men: approximately 2,500 kcal/day

These figures drop slightly with age. After 65, average needs fall to around 1,800 kcal for women and 2,100 kcal for men, mainly because muscle mass declines and people tend to be less active.

For children, teenagers, pregnant women, and breastfeeding women, the numbers are different. Pregnancy adds roughly 200 kcal/day in the third trimester only — not for the full nine months, despite the "eating for two" myth.

Calorie quality matters more than calorie quantity

Two thousand calories of whole grains, vegetables, lean protein, and fruit will keep you fuller and healthier than 2,000 calories of processed food, sugary drinks, and takeaways. The calorie number is the same, but the effect on your body isn't.

The NHS Eatwell Guide breaks this down practically: roughly a third of your plate should be starchy carbohydrates (preferably wholegrain), a third should be fruit and vegetables, and the remainder split between protein sources, dairy or alternatives, and small amounts of oils and spreads.

Ultra-processed foods (ready meals, crisps, sugary cereals, fast food) tend to be calorie-dense but nutrient-poor. They're also designed to be easy to overeat. Reducing ultra-processed food intake is one of the simplest changes you can make for both weight management and general health.

If you're trying to lose weight

Weight loss requires eating fewer calories than you burn. NICE recommends a deficit of 500-600 kcal per day below your maintenance level, which typically produces weight loss of about 0.5 kg (roughly 1 lb) per week. That pace feels slow but it's sustainable and far more likely to stick than crash dieting.

Very low-calorie diets (below 800 kcal/day) should only be followed under medical supervision. They risk nutrient deficiencies, gallstones, and muscle loss. They also tend to be followed by rapid regain once you stop.

If you've been restricting calories and not seeing results, there may be a medical factor. Thyroid dysfunction, polycystic ovary syndrome (PCOS), insulin resistance, and cortisol imbalances can all make weight loss more difficult. Blood testing can identify or rule out these conditions.

When calorie counting doesn't help

For some people, calorie counting becomes obsessive or triggers disordered eating. If tracking food intake makes you anxious, rigid, or preoccupied with food to the point where it affects your quality of life, stop counting.

Eating regular meals, choosing whole foods over processed ones, listening to hunger and fullness signals, and staying active are all effective approaches that don't require a calculator. If your relationship with food feels complicated, a GP conversation is a reasonable place to start.

How we can help

We offer weight management consultations that include body composition analysis, blood tests to check for underlying metabolic factors (thyroid function, HbA1c, cholesterol, vitamin levels), and personalised dietary guidance.

For patients who qualify, we also prescribe weight loss medications including GLP-1 receptor agonists (such as semaglutide). These are prescribed as part of a structured programme, not as a stand-alone fix.