How many calories should you eat to lose weight?

What is maintenance calories (TDEE)?

Your Total Daily Energy Expenditure (TDEE) is the number of calories your body burns in a day, including everything from breathing and digestion to walking and exercise. Eating at this level keeps your weight roughly stable, which is why it's often called your maintenance calories.

TDEE is influenced by your age, sex, height, weight, body composition, and activity level. It's not a fixed number - it changes as your weight, muscle mass, and lifestyle change, which is why it's worth recalculating every few weeks as you progress. Using a TDEE calculator, such as the one built into Nutari, gives you a solid starting estimate based on trusted formulas rather than guesswork.

The maths behind a calorie deficit

Weight loss ultimately comes down to energy balance: if you consistently consume less energy than you expend, your body draws on stored fat to make up the difference.

A commonly used rule of thumb is that roughly 7,700 kcal equates to about 1kg of body fat (or around 3,500 kcal per pound). This means a daily deficit of 500 kcal could lead to losing approximately 0.5kg (about 1lb) per week, all else being equal.

• 500 kcal/day deficit ≈ 0.5kg (1lb) lost per week
• 250 kcal/day deficit ≈ 0.25kg (0.5lb) lost per week
• 1,000 kcal/day deficit ≈ 1kg (2lb) lost per week

These figures are useful estimates rather than guarantees - individual results vary due to hormones, water retention, sleep, stress, and how accurately intake is tracked.

How to set a sensible deficit

Rather than picking an arbitrary calorie target, it's more effective to base your deficit on a percentage of your TDEE. A deficit of around 10–25% below maintenance is generally considered a sensible, sustainable range for most adults.

• 10–15% deficit: A gentle approach, useful for those newer to dieting, with less muscle to spare, or aiming for slow, steady progress.
• 15–20% deficit: A moderate, commonly recommended range that balances noticeable progress with manageable hunger.
• 20–25% deficit: A more aggressive approach that can work short-term for some people, but is harder to sustain and carries a higher risk of muscle loss and fatigue.

Once you have your TDEE, apps like Nutari can help you apply this percentage automatically and translate it into a daily calorie and macro target, adjusting protein, carbohydrate, and fat splits to help preserve muscle and support energy levels while you're in a deficit.

What's a realistic rate of weight loss?

For most adults, losing around 0.25–1kg (0.5–2lb) per week is considered a realistic and sustainable pace. Faster loss is often driven mainly by water weight rather than fat, particularly in the first week or two of a new plan.

Slower, steadier loss tends to be easier to maintain long-term, is more likely to preserve muscle mass, and reduces the physical and psychological toll that comes with very restrictive dieting. If you're also strength training, a more modest deficit can help support muscle retention, so more of the weight lost comes from fat.

Why crash diets backfire

It can be tempting to cut calories drastically for quicker results, but very low-calorie diets often work against you. Common issues include:

• Muscle loss: Severe deficits increase the risk of losing lean tissue alongside fat, which can slow metabolism over time.
• Fatigue and poor performance: Low energy availability affects concentration, mood, workouts, and daily life.
• Nutrient shortfalls: Very restricted eating makes it harder to get enough protein, fibre, vitamins, and minerals.
• Rebound eating: Extreme restriction often increases hunger and cravings, making overeating and regaining weight more likely once the diet ends.

A moderate, well-planned deficit - paired with adequate protein and some resistance exercise - tends to produce more durable results than an extreme, short-term approach.

Minimum calorie floors and when to get support

Regardless of how large your calculated deficit is, there are general minimum intake floors that most guidelines suggest not going below without medical supervision: broadly around 1,200 kcal/day for women and 1,500 kcal/day for men, though individual needs vary based on size, activity, and health status.

If your calculated target falls below these levels, if you have a medical condition, take medication, are pregnant or breastfeeding, or have a history of disordered eating, it's important to speak with a doctor or registered dietitian before starting a calorie-restricted plan. This guide is educational and not a substitute for personalised medical advice.