How Many Calories to Eat Per Day to Lose Weight

How many calories should you eat a day to lose weight? For most UK adults, reducing daily intake by around 500 calories below your personal maintenance level supports gradual, sustainable weight loss of roughly 0.5 kg per week. The NHS suggests approximately 2,000 calories per day for women and 2,500 for men to maintain weight, placing typical weight-loss targets between 1,500 and 2,000 calories daily. However, individual needs vary based on age, sex, activity level, and health conditions, so a personalised approach guided by a GP or registered dietitian is always preferable to following a generic number.

How many calories should you eat a day to lose weight?

Most adults can lose weight by eating around 500 calories below their maintenance level, typically 1,500 to 2,000 calories per day, though individual needs vary and personalised advice is preferable.

Most adults in the UK can achieve gradual, sustainable weight loss by reducing their usual daily calorie intake by around 500 calories below their personal maintenance level, which typically produces a loss of roughly 0.5 kg per week. The NHS advises a general daily intake of around 2,000 calories for women and 2,500 for men to maintain weight, so a weight-loss target often falls in the range of 1,500 to 2,000 calories per day depending on sex, age, and activity level.^[1][2] These are starting points rather than fixed rules, because individual needs vary considerably and a personalised assessment is always preferable.

Very low-calorie diets, generally defined as fewer than 800 calories per day, should only be followed under medical supervision.^[3][4] Eating too little can lead to nutrient deficiencies, muscle loss, fatigue, and other health complications. NICE guidance on obesity management emphasises that any dietary approach should be nutritionally complete and sustainable over the long term, and that structured total diet replacement programmes at this level require clinical oversight.

For those considering structured weight management support, a range of options exists, from NHS-based programmes to regulated online services. Bolt Pharmacy is a GPhC-registered UK online pharmacy offering online weight-management consultations, with prescriber review and pharmacist support, where clinically appropriate treatment may be considered.

Rather than focusing solely on a single calorie number, most dietitians and clinicians recommend combining a modest calorie reduction with increased physical activity and attention to food quality. This combined approach tends to produce better long-term outcomes than calorie restriction alone.

What factors affect your personal daily calorie target?

Your calorie target depends on your age, sex, height, weight, activity level, body composition, and any hormonal or metabolic conditions, all of which determine your total daily energy expenditure.

Your personal daily calorie target for weight loss depends on several interconnected factors, including your age, sex, height, current weight, and how physically active you are. These variables determine your total daily energy expenditure (TDEE), which is the number of calories your body burns across all activities in a day. A calorie deficit must be calculated relative to your own TDEE, not a population average.

Key factors that influence your calorie needs include:

• Basal metabolic rate (BMR): The calories your body burns at rest to maintain basic functions such as breathing and circulation. BMR tends to decrease with age and is generally higher in people with greater muscle mass.^[1][13]

• Physical activity level: Someone with a sedentary desk job burns significantly fewer calories than someone in a physically demanding role or who exercises regularly.

• Body composition: Muscle tissue burns more calories at rest than fat tissue, so two people of the same weight may have different calorie requirements.

• Hormonal and metabolic conditions: Conditions such as hypothyroidism or polycystic ovary syndrome (PCOS) can affect metabolism and make weight loss more challenging.^[10][10]

• Medications: Some medicines, including certain antidepressants, corticosteroids, and antipsychotics, can influence appetite and weight.^[8]

Sex also plays a meaningful role. Men generally have higher BMRs due to greater average muscle mass, which is why standard calorie guidance differs between men and women. Pregnancy and breastfeeding further alter calorie requirements, and weight-loss diets are not appropriate during these periods without specialist medical advice. If you are unsure how these factors apply to you, a GP or registered dietitian can help you calculate a personalised target.

How do you work out a safe calorie deficit for weight loss?

A safe deficit of 500 to 600 calories below your total daily energy expenditure supports gradual loss of around 0.5 kg per week; intakes below 800 calories per day require medical supervision.

A safe calorie deficit for weight loss is generally accepted to be around 500 to 600 calories per day below your total daily energy expenditure, which supports a gradual loss of around 0.5 kg per week without placing excessive strain on the body. This rate of loss is considered sustainable and is less likely to result in muscle loss or nutritional deficiencies compared with more aggressive restriction. NICE guidance on obesity management supports a 600 kcal per day deficit approach as a basis for structured weight-loss programmes.^[3][4]

To estimate your deficit, you can follow these steps:

1. Estimate your BMR using a validated equation such as the Mifflin-St Jeor formula, which takes into account your weight, height, age, and sex. Note that all such equations provide an estimate rather than a precise figure.
2. Multiply by an activity factor to arrive at your TDEE. For example, a lightly active person multiplies their BMR by approximately 1.375.
3. Subtract around 500 to 600 calories from your TDEE to set a daily calorie target that supports gradual weight loss.

For example, if your TDEE is 2,200 calories, a target of around 1,600 to 1,700 calories per day would represent a reasonable deficit for most people. UK clinical practice does not set universal minimum calorie floors in the way some other guidelines do; instead, NHS and NICE guidance focuses on the deficit size and nutritional completeness of the diet. Intakes below 800 calories per day are classified as very low-calorie diets and should only be undertaken as part of a supervised programme, as they carry a risk of nutritional inadequacy.

It is also worth tracking your intake honestly, as research consistently shows that people tend to underestimate how much they eat.^[11][12] Using a food diary or a validated app can improve accuracy. If weight loss stalls despite a consistent deficit, this may reflect metabolic adaptation, and a review with a GP or dietitian is advisable rather than cutting calories further.

Which foods help you feel full on fewer calories?

Lean proteins, high-fibre vegetables, pulses, whole grains, and water-rich fruits promote satiety and help manage hunger effectively while keeping calorie intake low.

Foods that are high in protein, fibre, and water content are among the most effective at promoting satiety, meaning they help you feel full for longer while contributing fewer calories overall. This is sometimes described as eating foods with a low energy density, where a large volume of food provides a relatively modest calorie load.

Some of the most useful food groups for managing hunger on a calorie deficit include:

• Lean proteins: Chicken breast, fish, eggs, low-fat dairy, legumes, and tofu all help stimulate satiety and support the preservation of muscle mass during weight loss. Evidence suggests protein is particularly effective at promoting fullness compared with carbohydrate or fat at equivalent calorie levels.^[14][15]

• High-fibre vegetables: Broccoli, spinach, courgette, peppers, and leafy greens are very low in calories but high in volume and fibre, slowing digestion and prolonging fullness.

• Pulses and legumes: Lentils, chickpeas, and kidney beans combine protein and fibre, making them particularly effective at reducing hunger between meals.

• Whole grains: Oats, wholemeal bread, brown rice, and barley release energy more slowly than refined carbohydrates, helping to stabilise blood sugar and reduce cravings.

• Fruit with high water content: Berries, melon, and citrus fruits provide sweetness, fibre, and hydration with relatively few calories.

Drinking water before and during meals may help some people manage overall intake, though the evidence for this effect is modest. Ultra-processed foods tend to be calorie-dense and low in fibre; some research suggests they may be associated with higher overall energy intake, though the mechanisms are still being studied.^[16][17] Prioritising minimally processed, whole foods is a practical strategy that aligns with NHS Eatwell Guide recommendations and supports both calorie control and overall nutritional quality.

When should you talk to your GP about losing weight?

See your GP if your BMI is 30 or above, you have a weight-related health condition, or you have a history of an eating disorder, pregnancy, or a chronic condition affected by dietary changes.

You should talk to your GP about losing weight if you have a body mass index (BMI) of 30 or above, or if you have a BMI of 25 or above alongside a weight-related health condition such as type 2 diabetes or high blood pressure.^[4][5] For some ethnic groups, including people of South Asian, Chinese, Black African, and Middle Eastern backgrounds, UK guidance recognises that health risks associated with excess weight can occur at lower BMI thresholds, typically from around 27.5 kg per square metre, and your GP can advise on what applies to you. Your GP can assess whether an underlying medical condition is contributing to weight gain and can refer you to specialist services where appropriate. Access to specific services and treatments depends on local commissioning and relevant NICE guidance.

There are also specific circumstances where seeking GP advice before starting any calorie-restricted diet is particularly important:

• You have a history of an eating disorder, as calorie counting can be harmful in this context.

• You are pregnant or breastfeeding, as calorie restriction is not appropriate during these periods.

• You have a chronic condition such as type 1 diabetes, kidney disease, or a cardiovascular condition that may be affected by dietary changes.

• You are taking medications that interact with diet or affect weight.

• You experience unexplained or rapid weight loss, which may indicate an underlying medical cause requiring investigation.

NICE guidance on obesity sets out a tiered approach to weight management, ranging from brief advice and lifestyle support through to specialist multidisciplinary services and, where clinically appropriate, pharmacological treatment.^[4][5] Your GP or an Integrated Care Board (ICB)-commissioned service can help determine which level of support is right for you.

If you feel unwell during a calorie-restricted diet, such as experiencing dizziness, persistent fatigue, or heart palpitations, contact your GP promptly. For urgent concerns, contact NHS 111 for advice.

Scientific References

1. Understanding calories.
2. Calories and weight loss – calorie counting.
3. Overweight and obesity management (NG246) – Physical activity and diet chapter.
4. Overweight and obesity management (NG246) – full guideline.
5. Overweight and obesity management (NG246) – Planning and delivering services chapter.
6. Overweight and obesity management (NG246) – Identifying and assessing overweight chapter.
7. Overweight and obesity management (NG246) – economic plan: low-energy total replacement diet.
8. Overweight and obesity.
9. How to lose weight.
10. Polyendocrine metabolic ovarian syndrome (PMOS) and diet.
11. Schoeller DA. How accurate is self-reported dietary energy intake? Am J Clin Nutr. 1990..
12. Lichtman SW et al. Discrepancy between self-reported and actual caloric intake and exercise in obese subjects. N Engl J Med. 1992..
13. Mifflin MD et al. A new predictive equation for resting energy expenditure. Am J Clin Nutr. 1990..
14. Differences in appetite, food intake, and gastric emptying responses to protein intake by older adults varying in level of physical activity. Appetite. 2025..
15. Effect of Lamb and Soy Protein on Postprandial Glycaemic, Insulin and Appetite Responses to Potato, Pasta and Rice in Macronutrient-Equalised Meals. Nutrients. 2025..
16. A Critical Review of the Science on 'Highly' Processed Food Intake and Body Weight. Advances in Nutrition. 2025..
17. Interpreting ultraprocessed food trial evidence: evidentiary limits, reporting practices, and policy relevance. Am J Clin Nutr. 2025..

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