Trying to lose weight? You need to be in a calorie deficit, and that means eating and drinking fewer calories than you burn.
There are two ways to create a calorie deficit:
- Reduce Calorie Intake: Change What and How Much You Eat
- Increase caloric expenditure – in the form of exercise
How does being in a caloric deficit help you lose weight? It puts you in a ‘catabolic’ state, when the body breaks down muscle and fat for energy.
If you cut 500 calories a day from what you normally eat, you can expect to lose about 1 pound (0.5 kg) a week, which is a healthy amount according to CDC Guidelines (opens in a new tab). the best exercise machines for weight loss (opens in a new tab) it can also help reduce body fat.
Here’s what the research — and the experts — have to say about being in a calorie deficit.
What is a calorie deficit?
Calories are the units of energy we get from food and drinks. To lose body fat, you need to be in a calorie deficit, which means eating fewer calories than you burn.
Nutritionist and PT Alex Parren says, “A calorie deficit is when you take in fewer calories than you expend in a day. Every human being has a unique Basal Metabolic Rate (BMR), which indicates how many calories your body burns just performing normal everyday functions, such as breathing, digesting food, eliminating waste products, and cognitive functions.
“Factors that affect BMR include age, gender, height, and body weight. Think of your BMR as the number of calories you would burn if you stayed in bed and slept all day. It doesn’t take your lifestyle into account, and most people’s BMR will be pretty low: around 1,500 calories for adults.”
On an average day, you’ll burn more calories than this, since you’ll be awake and moving. In general, an average woman needs about 2,000 calories a day to maintain her weight and 1,500 to lose 1 pound a week. The average man needs to consume about 2,500 to maintain the same weight, or 2,000 to lose 1 pound per week.
Research published in Frontiers in physiology (opens in a new tab) suggests that doing muscle-building exercises in conjunction with a calorie deficit will also help the body prioritize losing body fat over just muscle.
What role does it play in weight loss?
The body uses the calories it gets from food to fuel its metabolism, digestion, and physical activity. When the number of calories you eat equals the number of calories you burn for energy, your weight will remain stable.
Once your body’s energy needs are met, the extra calories are stored, some in the muscles as glycogen (the main source of fuel for our cells), but most as fat. Therefore, if you eat more calories than you burn, known as excess calories, this will lead to weight gain. Conversely, if you eat less food than you need for energy, you will lose weight.
Parren says, “There are several studies that show that being in a calorie deficit is the only way to lose weight. Any type of diet, be it the paleo diet (opens in a new tab)the board diet (opens in a new tab)either keto (opens in a new tab) – rely on a calorie deficit to work. It is recommended not to exceed a deficit of 500 calories a day.
“However, I would advise people to achieve this deficit by burning more calories, rather than restricting food intake. That is, burn your 500 calories a day through cardio and resistance training, rather than reducing the amount you eat. The reason for this is that it is less likely to trigger cravings and eating disorders,” she says.
How to achieve a caloric deficit?
To achieve a calorie deficit, you must first calculate your Basal Metabolic Rate (BMR), the number of calories your body needs to meet its most basic (basal) vital needs at rest. There are many calculators online that will help you do this.
“Once you know your BMR, you need to include factors like how active you are and how much you exercise,” says Parren. This calculation is your total daily energy expenditure, or TDEE, which is a more accurate representation of how many calories you actually burn in a day.
“Your TDEE will take into account how many steps you take in a day, how active your job is (sitting at a desk all day versus manual labor), and even activities like gardening or walking your dog. Once you have a figure for your TDEE, you can calculate how many calories you would need to eat to be in a deficit.
“A caloric deficit is any number down your TDEE and a pound of fat equals approximately 3,500 calories. So if you are in a 500 calorie per day deficit for seven days, you will lose about 1 pound per week.
“To be more specific, if your TDEE is 2,500 calories, you would need to eat 2,000 calories per day to lose 1 pound per week.”
Remember that once you start losing weight, you’ll need to recalculate your TDEE to calculate your new daily calorie deficit figure. “Once you’ve lost some weight, eat at a maintenance level, the same amount of calories as your TDEE, to make sure you don’t gain the weight back,” says Parren.
