Most adults don’t need to “burn” a specific number of kilojoules per day in exercise alone; instead, the focus is on your total daily energy balance (what you eat vs what you use through metabolism and activity). A common starting point is to aim for a moderate kilojoule deficit of about 2,000–2,500 kJ per day below your maintenance needs if your goal is steady, healthy weight loss.

Key idea: balance, not a magic number

  • The average adult needs about 8,700 kJ per day from food to maintain weight, but this varies with age, sex, body size, and activity level.
  • To lose weight, people often aim to either:
    • Eat fewer kilojoules, and/or
    • Burn more through movement, creating a total deficit of roughly 2,000–2,500 kJ per day for gradual, sustainable loss.

How many kilojoules to burn in exercise?

Instead of a fixed target, think in ranges and adjust:

  • If you create most of your deficit with diet, you might burn 500–1,000 kJ per day with exercise and cut the rest from food.
  • If you prefer more movement, you might burn 1,500–2,500 kJ per day from exercise on active days and eat closer to maintenance.
  • Health guidelines suggest at least 150 minutes of moderate or 75 minutes of vigorous activity per week for general health; this usually adds up to several thousand kilojoules burned across the week.

Simple way to set your own target

  1. Estimate maintenance: Use an online TDEE or kilojoule calculator to find how many kJ you need to maintain your current weight (often near that 8,700 kJ average but personalized).
  1. Choose a deficit:
    • Mild loss: ~1,000–1,500 kJ below maintenance per day.
    • Moderate loss: ~2,000–2,500 kJ below maintenance per day.
  1. Split it:
    • Part from eating a bit less.
    • Part from moving more, aiming for a burn that feels challenging but sustainable most days of the week.

Safety notes

  • Very low intake (for example, consistently under about 5,000 kJ per day for adults) or extreme exercise plans can harm heart health, hormones, and muscle mass.
  • If you have existing health issues, are on medication, or have a history of disordered eating, a doctor or dietitian should help set your kilojoule and exercise targets.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.