It depends on how large you are and the amount of weight you have to lose. A larger person with more fat tends to have larger Total Energy Expenditure so they can have a 1000 – 15000 calorie deficit and still be okay. But, for someone who needs to lose 10 – 20 pounds of weight a larger deficit could be detrimental to their weight loss as it could result in their metabolism shutting down. For these clients, I generally recommend a deficit no larger than 700 calories.
Based on my years of experience helping thousands of people sustainably lose weight I have come up with these general deficits for weight loss –
BMI greater than 30 (obese) = 1000 – 1500 calorie deficit
BMI of 25 – 29 (overweight) = 700 – 1000 calorie deficit
BMI less than 25 (those that want to lose 5 – 10 lbs.) = 500 – 700 calorie deficit
If you want to find out your customized total energy expenditure and your optimum deficit of calories for weight loss please visit www.EatingFree.com and use our free online tools.