How Many Calories Should I Eat a Day?

Trying to work out how many calories to eat can be a minefield. There's so much differing advice out there on what to eat and, besides, it all depends on your goals.

One of the questions the experts at 12WBT are most often asked is: how many calories should I eat a day?

The answer depends on a range of factors including your gender, your body mass index (BMI) and your weight goals - but we're here to help you figure it all out so you can decide how much to eat.

What Are Your Goals?

First of all, ask yourself whether your primary objective is to lose weight, maintain your weight or perhaps even put on a little weight if your BMI is in the underweight category.

(A healthy BMI should be within the range of 18.5 to 24.9 - which you can determine with this BMI calculator.

Your objective can change over time as your weight increases or decreases, and this will affect your required calorie intake and how much to eat. So make sure you regularly keep an eye on your weight and your BMI.

If you don't monitor those numbers and what you eat, it's easy for kilos to start creeping back on - or even for too many to fall off.

How Calories Affect Your Weight

How much you weigh is a result of three main things: your basal metabolic rate (BMR - see below), the number of calories you eat and drink and the number of calories you burn through exercise.

Your BMR is the number of calories your body would burn in a day if you didn't move at all. The more muscular you are, the higher your BMR is, because muscle mass needs energy just to maintain itself.

That means that you do have some control over your metabolism by developing your muscles.

As for the two other elements of the equation, food and exercise, remember the simple formula: calories in, calories out.

In other words, you need to play around with your calorie intake through what you eat and drink (calories in) and exercise (calories out) to strike the right balance in order to achieve your goals.

And of course, doing more exercise can also affect your BMR as you develop more lean muscle, so it's a win-win situation.

We'll help you figure out exactly how many calories you need to eat every day depending on your weight goal.

Let's take a look at six different scenarios and how they can help you decide how many calories to eat.

Goal 1: Calories for Weight Loss in Women

When you're trying to lose weight, you have to burn more calories than you eat and drink. You can do that by cutting calories or exercising - but by far the best way to lose weight quickly, efficiently and healthily is to do both.

Simply put, you need to eat less and move more.

This might seem obvious, but so many diet plans try to convince you that you'll lose weight by cutting out certain food groups.

Forget all that hocus-pocus about "don't eat carbs" or "only eat protein" and remind yourself: calories in, calories out.

So, every little thing you eat and drink during the day (yes, even if you eat that one little lolly!) counts towards your daily calorie intake, and every minute you exercise rather than watching TV counts towards your daily calorie burn.

But keep in mind that all the calories you eat and drink aren't created equal.

When you decide to eat fewer calories for weight loss, you have to make sure you're not eliminating essential vitamins and nutrients in favour of unhealthy processed foods.

We'll help you make the right food choices in our article on how many calories you need to eat to lose weight.

Goal 2: Calories for Weight Maintenance in Women

If you've reached your goal weight - which should be equivalent to a BMI of 18.5 to 24.9 - congratulations are in order!

While you should celebrate your achievement, it's important not to lose sight of your goals or forget all the healthy habits you've worked so hard to put into place.

Once you've been at your goal weight for two weeks, you'll need to adjust how much you eat to shift into the weight-maintenance phase. The main change will be an increase in the number of calories you eat and drink.

While to some people this is a very welcome change, for others it can be quite difficult to jump off the weight-loss train.

Watching the kilos drop off can become addictive, but it's important to stop before you lose too much - being underweight has its health risks too! (For more on this, see Goal 3 below.) So it's not a good idea to eat at the same rate as when you were aiming for weight-loss.

After increasing the number of calories you eat to the maintenance level, you'll have to continue monitoring your weight to make sure you stay within 1kg to 2kg of your goal weight.

Because everyone is different, you might find that you're starting to put on weight again, in which case you should cut back and eat fewer calories until your weight stabilises. And if the weight is still dropping off, you'll have to boost your calorie intake a bit more.

Keep exercising as hard as when you were trying to lose weight. Don't scale back on your workouts in a bid to halt your weight loss - you can always adjust how many calories you eat if need be.

To find out exactly how many calories you should eat each day to maintain your weight, read our article on calories for women.

Goal 3: Calories for Weight Gain in Women

While it might seem unbelievable to people who have struggled with being overweight their whole lives, some women have the opposite problem - their low BMI means they are underweight and need to eat more.

If you're thinking "I wish I was in their gang!" keep in mind that being underweight comes with its own set of health problems, including infertility, osteoporosis, anaemia and immune system deficiencies.

Being too thin isn't necessarily voluntary - some women struggle to put on weight and eat enough, while others lose too much through exercise, breastfeeding or illness.

As long as you've ruled out a medical problem as the cause of your difficulty gaining weight and you have the all-clear from your doctor, there are healthy ways to help you reach your weight-gain goals. And for that you'll need to apply some thought to what you eat.

In order to put on weight, you need to eat and drink more calories than you burn. But that doesn't mean you have a licence to eat junk food and avoid exercise!

Quite the contrary: it's essential to eat a healthy diet and maintain an active lifestyle to ensure you keep your health on track.

You just have to increase the amount of calories you eat by adding healthy foods to your diet. For more, read our article on calories for women (see above).

Goal 4: Calories for Weight Loss in Men

Just like their female counterparts, men who are trying to shed kilos need to cut back on the number of calories they eat and increase the number of calories they burn.

The major difference is that men need to eat more calories than women do because they generally have less body fat and more muscle than women, which means that they burn more calories.

But before you speed-dial the pizza shop, keep in mind that the extra calories should come mostly from eating protein and healthy carbohydrates - not unhealthy processed food!

And you also need to work out just as hard to burn off the calories you eat and drink.

So how many calories should you eat a day to reach your goals and which foods should you choose? We reveal all in our article on how many calories you need to eat to lose weight.

Goal 5: Calories for Weight Maintenance in Men

You've finally reached your goal weight and you're in the healthy BMI range of 18.5 to 24.9 - well done!

Now you'll have to make some adjustments to what you eat to ensure you maintain that number you've worked so hard to see on the scales.

You'll need to slightly increase the amount you eat, and thus your daily calorie intake, to stop losing weight - which can be just as hard for men as it is for women.

It's so gratifying to see the weight drop off and to feel so good about yourself, but less isn't always more.

Once you've reached your goal weight, you should aim to stay within 1kg or 2 kg of it.

After you've added some calories back into your diet, it'll be just as important as before to keep an eye on the scales.

If you notice you're gaining again or continuing to lose, you'll have to tweak the foods you eat and your calorie intake until you get it right and your weight remains steady.

And don't even think about cutting back on the intensity of your workouts to avoid burning calories! It's better to play around with how much you eat than to skimp on your exercise.

We tell you just how many calories you should eat and drink to keep your weight stable in our article on calories for men.

Goal 6: Calories for Weight Gain in Men

You might be one of those guys who just can't seem to put on weight, no matter how much you eat - and exercise might be contributing to it, especially if you do a lot of cardio.

As long as you've consulted your doctor to make sure it's not due to an illness and you've been given the green light to engage in a healthy eating and exercise program, you can follow our strategies to add kilos to your frame.

You'll need to eat and drink more calories than you burn in order to put on weight.

While many skinny guys think they can get away with eating junk food because they don't gain weight, they're still copping the negative health effects of processed food and missing out on essential nutrients.

Don't make that mistake - gain weight the healthy way by eating more whole, unprocessed foods rather than junk foods containing lots of calories but few nutritional benefits.

For tips on adding healthy foods to your diet and to find out just how much you need to eat each day in order to gain weight, read our article on calories for men (see above).

To find out how many calories are in the foods you eat, see our article on using a calorie calculator.