Short answer: it depends on you. Most adults burn roughly 8,700 kJ per day (about 2,080 kcal) to maintain weight, but exact needs vary by age, sex, weight, height, and activity level. If you’re aiming to lose weight, you’ll typically want a modest daily energy deficit (burn more than you consume), often referenced as about 2,000 kJ per day or more depending on your goals and starting point. For personalized guidance, a calculation of your Total Daily Energy Expenditure (TDEE) based on your details is best. Key points to consider

• What to aim for: to maintain weight, target around 8,700 kJ daily for many adults; to lose weight, create a deficit (e.g., 2,000–4,000 kJ/day depending on how quickly you want to lose weight and other factors).
• Activity matters: increasing daily activity raises the total kilojoules burned, making it easier to create a deficit or meet higher energy needs.
• Individual variation: factors like muscle mass, hormonal status, pregnancy, and age can shift your energy requirements.

How to estimate your needs

• Basal metabolic rate (BMR) plus activity: BMR is your energy expenditure at rest; multiply by an activity factor to estimate your TDEE.
• Use a reputable online calculator or consult a healthcare professional to get a personalized value, especially if you have medical conditions, are pregnant, or are an athlete.

If you’d like, share a few details (age, sex, height, weight, and typical activity level), and I can help estimate your likely daily kilojoule needs and outline a plan aligned with your goals.