A) What is a calorie deficit?
A calorie deficit occurs when the number of calories a person consumes in a day is smaller than the number of calories they burn.
The body needs to burn a certain number of calories to perform all its functions each day.
How many calories a person needs each day varies based on their:
sex
age
physical activity levels
height
weight
body composition
A person can create a calorie deficit by reducing the number of calories they eat, increasing their activity levels, or both.
Is a calorie deficit enough to lose weight?
Maintaining a calorie deficit is an important part of weight loss, but it is not the whole picture. This is because calories are not the only thing to affect weight.
To lose 1-2lbs per week, a person would need to eat 500–1,000 calories fewer than the number of calories their body needs per day.
If a person is sedentary, meaning that they only move as much as they need to live independently but do not exercise or engage in other physical activities, they should start to get 30min. of exercise each day, if possible.
Also, the centers for disease control and prevention state that cutting calories does not necessarily mean feeling unsatisfied at meals.
A person can replace some higher calorie foods with lower calorie foods, increase their water intake, and eat more fiber to feel full.
How to create a calorie deficit
Once a person knows how many calories they need each day or week, they can work on creating a calorie deficit.
One lb of body fat contains about 3500 calories. For a person to lose 1 lb of fat in a week, they would need a deficit of 3,500 calories, or 500 calories per day, over that time. To lose 2 lb, a person would need a deficit of about 7,000 calories.
However, it is not advisable for a calorie deficit to exceed 7,000 calories per week.
The more physically active a person is, the more calories they will burn.
This increases the number of calories they need, which can make creating a deficit easier.
Risks of eating too few calories
If a person cuts too many calories and does not get enough necessary nutrients, they can experience some health problems.
The body needs a minimum number of calories to function properly. Cutting too many can increase the risk of health issues including:
not getting enough nutrients, which can interfere with gaining or maintaining bone mass
depriving the brain of necessary energy
decreasing metabolism
increasing the risk of developing gallstones
Some symptoms of not consuming enough calories include:
getting sick frequently
being unable to lose weight
experiencing negative changes in mood or behavior
having difficulty sleeping
Before cutting calories, a person should talk with their doctor or nutritionist. People with specific health conditions, such as diabetes, may need specialized diets to help them manage their condition.
Summary
Creating a calorie deficit may be helpful if a person wishes or needs to lose weight. A person can do this using a combination of diet and exercise.
They should try to focus on eating highly nutritious foods, drinking more water, and exercising regularly.
Formulas and online calculators are available to help people estimate how many calories they burn per day. From there, a person can estimate how many calories they should eat to create a calorie deficit.

