If you’ve ever tried to lose weight, you’ve probably heard that a calorie deficit is required.
But you may also wonder what this means exactly, or why it’s necessary to lose weight.
In this article, you’ll learn everything you need to know about a calorie deficit: what it is, nutrition how it affects weight loss, and how to achieve it in a healthy and sustainable way. What is a calorie deficit, and how much of it is healthy? What it is and why it is important for weight loss
Calories are the units of energy you get from food and drinks. If you eat fewer calories than you burn, you have a calorie deficit.
The calories you burn or consume on a daily basis – also known as calories burned – are made up of the following three components (1):Quiescent energy consumption (REE). REE refers to the calories your body uses at rest for functions that keep you alive, such as breathing and bloodstream.Thermal effect of food. It’s about the calories your body uses for digestion, absorption, and metabolism of food.Activity energy consumption. This refers to the calories you burn in sports activities and other activities, such as fidgeting or housework.
When you give your body fewer calories than it needs to cover these three components of calorie consumption, you’re putting your body in a calorie deficit. If you do this consistently over a longer period of time, it will lead to weight loss (1).
Conversely, you gain weight if you regularly feed your body more calories than it needs for these functions. This is called a calorie surplus.
A calorie deficit occurs when you permanently supply your body with fewer calories than it needs for calorie consumption. Calculation of calorie requirements
For most people, a calorie deficit of 500 calories per day is enough to lose weight, and it’s unlikely to have a significant effect on your hunger or energy levels (2).
To achieve this calorie deficit, you need to know what your calorie needs are. Maintenance calories are exactly the number of calories your body needs to meet energy needs.
You can use calorie calculators like the National Institute of Health’s Body Weight Planner. Such calculators estimate your calorie needs based on your weight, gender, age, height, and activity level (3).
Although calorie calculators give a good idea of your calorie needs, you can get a more accurate number by tracking your calorie intake and weight for 10 days (4).
Use a calorie measurement app to measure your calories and weigh yourself daily while maintaining your daily activity level. To get an accurate result, use the same scale, at the same time of day and in the same clothes (or not at all).
Your weight may fluctuate from day to day, but if your weight has otherwise remained stable over the 10 days, the average number of calories you’ve burned per day is a better representation of your calorie needs.
Divide the total number of calories you’ve burned in the 10 days by 10 to get your average daily calorie intake. Then subtract 500 calories from that number to determine your new daily weight loss goal.
For example, if you find that you’re eating 2,000 calories a day, your new daily calorie goal would be 1,500.
As you lose weight, your calorie needs will decrease over time and you’ll need to adjust your calorie intake to your weight loss goals (1).
However, to ensure healthy weight loss and adequate nutrient intake, women should consume no less than 1,200 calories per day, men no less than 1,500 calories (5).
You can estimate your calorie needs with an online calculator. You can get a more accurate figure by observing your calorie intake and weight for 10 days. Ways to Achieve a Calorie Deficit
You can achieve a calorie deficit by eating fewer calories or increasing your physical activity — or both.
However, it can be easier and more sustainable to achieve a calorie deficit through a diet than through exercise alone, as you may not have the time, energy, or motivation to exercise daily. What’s more, exercise doesn’t burn as many calories as many people believe (6, 7, 8, 9, 10).
In other words, it may be easier to eat 500 fewer calories each day than to burn that amount of calories through exercise. Nevertheless, it is recommended to do muscle-strengthening and aerobic exercises, as they have a positive effect on overall health (11).
The Department of Health and Human Services’ Physical Activity Guidelines for Americans recommend that adults engage in 150–300 minutes of moderately intense exercise or 75–150 minutes of vigorous exercise weekly (12).
Moderately intense exercises include brisk walking and light cycling, while examples of intense exercise include jogging and fast cycling.
The guidelines also recommend that adults perform exercises to strengthen major muscle groups — such as back, shoulders, chest, arms and legs — at least two days a week (12).
Engaging in muscle-strengthening activities helps your body lose body fat rather than muscle mass (13, 14, 15).
It’s probably more sustainable to achieve a calorie deficit through a diet than through exercise alone. However, physical activity is important for many aspects of health. Tips for a lower calorie diet
To achieve a calorie deficit, you don’t necessarily have to make drastic changes to your diet.
In fact, there are some strategies that can help you reduce your calorie intake to lose weight and maintain it — and they don’t even require calorie counting.
You may be able to eliminate several hundred calories from your diet by reducing or eliminating your consumption of sugary drinks such as soda, fruit juices, and specialty coffees.
Also, alcoholic beverages can contain a significant amount of calories.
The calories from these drinks don’t fill you up and, in excess, can lead to weight gain, heart disease and diabetes (16, 17, 18, 19). Limit highly processed foods
The sugar, fat and salt in highly processed foods, including sugary drinks, fast foods, desserts and breakfast cereal, make these high-calorie foods very tasty and encourage overconsumption (20, 21).
In fact, one study showed that people who were allowed to eat as much or as little as they wanted consumed 500 calories more per day on a highly processed food diet than on a minimally processed food diet (22).
Minimally processed foods are rich in vitamins, minerals, and fiber, and include foods such as lean protein, fruits, vegetables, nuts, and legumes. A diet rich in minimally processed foods will help you avoid overeating and ensure you’re getting the nutrients your body needs.
If your diet consists of a lot of highly processed foods, slowly start replacing those foods with as little processed ones as possible. For example, swap sugary cereal for oatmeal with fruit or chips for lightly salted almonds. Eat mainly home-cooked meals
When you prepare and eat your meals at home, you can control the ingredients and portion sizes – and therefore your calorie intake.
One study showed that people who cooked at home 6–7 times a week consumed an average of 137 fewer calories per day than people who cooked 0–1 time per week at home (23).
Eating home-cooked meals has also been linked to better quality diet, higher consumption of fruits and vegetables, lower body fat percentages and a lower risk of heart disease and diabetes (24).