Lots of people have different opinions on this question, but experts recommend you aim to lose around two pounds per week.

How many calories does this two pounds add up to for you, though? Different people have different calorie needs, so working it out requires some math.

The old equation of “calories in, calories out” is now considered to be outdated and too simplistic. To understand how many calories you need to lose weight, you have to understand the factors that influence how many calories you need to eat in the first place.

What has an effect on your calorific needs?

Your calorie needs vary at different times of your life, and these things all have an influence:

Activity level Age Pregnancy Body composition Illness or injury Health conditions, such as hypothyroidism

You also need to understand your basal metabolic rate, or BMR. Put simply, BMR is a measure of how many calories your body burns while it is at rest, performing essential functions such as breathing, pumping blood, and digesting food.

Once that is worked out, the total number of calories you need to maintain your current weight can then be calculated according to your age, height, weight, sex, and level of activity.

You can use an online calculator to help you determine your basal metabolic rate, but even this isn’t an exact number. Lainey Younkin, M.S., R.D.N, L.D.N, explains. “Think about your calorie needs as a range, rather than just one number. It’s based on your activity level, and you don’t do the same activities every day,” she says.

Not all calories are created equal

Most registered dieticians don’t believe that a calorie is just a calorie. Humans don’t eat calories, we eat food, and the calories eaten as part of a meal or snack contain nutrients like protein, fat, and carbohydrates.

Research shows that calories from certain foods, such as fruits, vegetables, whole grains, and beans create a different biological response in the body than the same number of calories from sugars, such as candy or soda.

It’s easy to consume 2,000 calories or more from sweetened foods, but they don’t contain key nutrients like fiber or fat, which help you to feel full.

How many calories equal two pounds of weight loss per week?

3,500 calories are the equivalent of one pound of weight. If you burn or remove 500 calories per day for one week, you will have a one-pound weight loss – in theory, at least. To lose two pounds a week, you would have to cut out or burn off 1,000 calories each day.

Nutritionists recommend focusing on the quality of the calories you’re eating, not just the quantity. Protein, fat, and fiber are the three nutrients that help promote a feeling of fullness, so you need to know which foods contain them.

This is just a starting point, though. People who want to make changes in their diet should learn to understand their calorie needs, and avoid restricting calories too much. Ultimately, if you want to lose weight, you need to restrict or burn more calories than you eat in any given day, but you need to find the right balance and goal number. This may take time as you adjust what feels right for your body while still getting the results you want.

The problem with extreme calorie restriction

Some diets recommend very low-calorie goals, such as below 1,200 a day. These levels of calorie restriction are not likely to sustain the energy needs of most healthy people for any length of time.

As well as not meeting your nutritional needs, restriction has an impact on your metabolism, which starts to conserve your energy when you go without enough calories for a period of time. You will lose water weight first, then muscle tissue, then your metabolism will slow down and try to conserve fat when you restrict calories severely.

This can have lasting impacts on health, and although the weight loss at first can be encouraging, it won’t last once you start eating normally again. You can also suffer from decreased bone density, hair breakage and impaired immunity as long-lasting effects.

So, what works best for weight loss?

Maika Luongo, M.S., R.D., L.D.N, is a dietician who recommends her clients try an individualized approach when it comes to weight loss, but she doesn’t rule out the basics of using calorie counting as an educational tool.

“Counting calories and/or using a calorie tracker raises awareness of actual calorie consumption, and it allows someone to visually see how much and what they’re eating,” she says. However, Luongo adds, “There’s no one-size-fits-all when it comes to losing weight.”

Mindful eating is recognized as a way of improving diet quality, and potentially leading to weight loss, although it’s not a fast route to get there.

The answer to lasting weight loss isn’t extreme diets and calorie restriction. Luongo says, “Weight loss isn’t easy, and it’s going to take some dedication, commitment and patience. The best approach is to eat a well-rounded diet and not deprive yourself of specific foods or food groups. Not every day is going to be perfect, and that’s OK. Pick up where you left off, and keep moving forward.”