Some diets today discourage counting calories, relying instead on having you calculate point values for certain foods. Others ask you to focus on eating (or not eating) certain types of foods, such as veggies or carbs. But knowing how many calories in a day you should eat—as well as how many you’re actually consuming—can be important information. This is true whether you’re trying to lose, gain or maintain weight, as well as stay healthy. So how can you figure out how many calories should you eat per day?
Eating a certain number of calories per day can help you achieve and maintain a healthy weight. Research further indicates that, when following a balanced diet, consuming the best number of calories for you can also help improve your health and boost longevity.
Calories count. You eat them, drink them and burn them every day. Understanding how many calories you should eat each day is one important part of developing healthy eating habits. And that’s true no matter if you’re trying to lose weight or maintain a balanced lifestyle.
When determining how many calories you should eat per day, it helps to first understand the established recommended calorie intakes. From there, you can consider other factors to find the calorie intake that is right for you given your body and health-related goals.
The right balance between the different nutrients that compose our daily diets (carbohydrates, fats, proteins, water, vitamins, and minerals) is just as significant as the overall food intake. In simple terms, if we consume more calories than we need on average, we will gain weight and if we consume less than we need on average, we will lose weight in fat, as well as muscle mass.
What Are Calories?
Calories measure the amount of heat required to increase the temperature of a liter of water by a single degree. So, what does that mean? Calories are measurement of energy. The number of calories in a food or drink determines the amount of energy stored in that food item.
Your body gets energy from those calories when you eat them. You’re constantly burning calories while your body does normal functions like breathing and thinking. You also burn calories doing physical activities.
In terms of nutrition and diet, kilocalories (“large calories”, symbol: kcal) are more commonly used to express the amount of energy value of particular foods. In the context of nutrition, the kilojoule (kJ) is the SI unit of food energy.
The total number of calories within a particular food is the sum of the amount of energy released by each of the components (protein, carbohydrates, and fats), minus the fiber content. Fiber is removed as humans are not able to fully digest it.
How Many Calories Should You Eat Per Day
Knowing the recommended calorie intake guidelines can provide a better idea of what your calorie range will be. These vary based on whether you are an adult, a teen, or a child.
Adults
The recommended calorie intake for adult women ranges from 1,600 calories per day to 2,200 calories per day according to the Academy of Nutrition and Dietetics.2
For men, the amount is slightly higher, ranging from 2,000 to 3,200 calories per day.
If you are somewhat sedentary or older, your calorie needs are likely toward the bottom of the range. If you are fairly physically active, pregnant, or breastfeeding, you may be closer to the top.
Teens
Calorie intake recommendations for teens vary based on age, sex, and activity level. A 13-year-old girl’s recommended intake ranges from 1,600 to 2,000 calories daily with a 2,000 to 2,600 recommended intake for a 13-year-old boy.3
These amounts increase slightly in the later teen years. For girls aged 14 to 18, the range is 1,800 calories per day to 2,400. For boys in this same age range, the recommended calorie intake is somewhere between 2,000 and 3,200 calories.
Children
Children between the ages of 2 and 3 years old need between 1,000 and 1,400 calories per day according to the National Institutes of Health.4 Where they fall in this range depends on how active they are.
At 4 to 8 years of age, the range starts at 1,200 calories daily and increases to 1,800 calories for girls and 2,000 calories for boys. At 9 to 13 years, the calorie range is 1,400 to 2,200 calories per day for girls and 1,600 to 2,600 calories daily for boys.
How Can You Calculate Your Daily Calories?
The calorie ranges listed above are very wide. To find a number closer to what you need, you can make use of various daily calorie calculators. With these, you fill in your sex, age, height and weight. You also estimate your activity level: sedentary, moderately active (includes walking 1.5 to 3 miles per day at 3 to 4 miles per hour), and active (walking more than 3 miles per day at 3 to 4 miles per hour).
Two online calorie counters will automatically assess how many calories you should ingest to either maintain or lose weight:
- The American Cancer Society’s calorie counter for adults over 19
- The National Institutes of Health’s Body Weight Planner
You can also figure your own daily calorie needs using these steps:
- Calculate your weight in kilograms. If you’re like most Americans, you know your weight in pounds. To translate to kilograms, divide that number by 2.2.
- Multiply the result by 30.
So, if you weigh 150 pounds, your weight in kilograms is about 68.19; multiplying this by 30 nets you a daily calorie count of 2046. If you are very active or very sedentary, you may need to add or subtract a few calories if you want to maintain your current weight.
Fitness experts at health clubs or gyms also may be able to figure your recommended daily calorie intake by measuring your oxygen consumption and carbon dioxide production.
Calories and Physical Exercise
Lifestyle choices have a significant impact upon the number of calories required to maintain a healthy weight. In simple terms, a person’s lifestyle falls into one of three categories depending on the extent of daily physical exercise: sedentary, moderately active or active.
The Harris Benedict Equation is a formula that uses the BMR and then applies an activity factor. For example, the recommended activity factor for a person with a job that requires moderately physical work and who engages in light exercise daily is 1.6. Multiplying the basal metabolic rate (BMR) by the activity factor can aid in calculating the daily energy expenditure, depending not only on the age and sex, but also the daily activity.
Quality of Calories, Not Just Quantity
Consuming the right number of calories is a good first step towards achieving a healthier body. However, you should know that not all calories are equal. Keeping to the calorie count on a diet consisting of only sugary cakes, meat dishes, or a glass of wine is far from ideal. This is because your body needs a variety of vitamins and minerals, as well as fibre to function properly.
One simple way to achieve this is to follow My Healthy Plate guidelines for a balanced meal. Fill your plate with 1/2 plate of fruit and vegetables, 1/4 of wholegrains, and 1/4 of meat and others.
Eating healthy is not limited to eating the right amount and the right mix. It is also important for optimum nutrition to choose healthy foods prepared with healthier options and ingredients. Steamed chicken, for example, is far healthier than deep-fried chicken.
For example, wholegrains are healthier than refined grains (white rice or bread) as they contain more vitamins, antioxidants and fibre. In addition, they also keep you filling full for longer, which helps reduce the risk of overeating. Choosing healthier cooking oils are also important as they can affect your body’s good (HDL) and bad (LDL) cholesterol levels.
Reaching Your Goal Weight
How Many Calories Do You Need If You Want To Lose Weight?
The old rule of thumb used to be that it takes about 3,500 calories to gain one pound of weight. Put another way, you need to cut 3,500 calories if you want to lose a pound. Under this thinking, if you cut 500 calories from your daily diet (either through diet or exercise, or a combination of both), you would lose one pound per week.
However, in recent years, researchers have found this to be an oversimplification of a complicated process. In 2013, scientists analyzed seven previous weight-loss studies where people’s food intake was closely monitored, and found that instead of losing a pound for every 3,500 calories lost, people’s weight loss amounts varied. Men tended to lose weight faster than women, and younger people lost faster than older people, with variations within those groups.
As people lost weight, it took longer to lose more weight. They hit plateaus where they had to cut more calories than 3,500 to lose a pound. The National Institutes of Health still recommends dieters try cutting 500 calories a day, but cautions not to expect a precise “calories-in, calories-out” equation. You may not lose that pound as easily as you might hope.
To Gain Weight
If you are trying to gain weight, your daily calorie goal will include a calorie surplus. The key to making this gain healthy involves following a few simple guidelines:12
- Eat high-quality high-calorie foods, such as high-protein meats, healthy fats, and whole grains
- Eat more often (this helps if you get full quickly)
- Add extra calories to your meals, such as by putting nuts on your morning oatmeal
- Drink nutrient-rich shakes
- Incorporate strength training into your exercise routine
To Maintain Weight
Several pieces of research have sought to find the best ways to maintain one’s current weight, especially after successful weight loss. One analysis of many of these studies reports that results are mixed as to what strategies may work best.13
However, many of these studies did find that following a higher-protein diet might help with weight maintenance. A diet rich in omega-3 fatty acids and polyphenols was also suggested as an effective approach to sustaining a healthy weight.
When Is It Dangerous to Consume Too Few Calories?
Also keep in mind that it’s possible to eat too few calories. In general, say experts, going lower than 1,000 calories per day (especially without medical supervision) means you might not be getting enough nutrients to stay healthy.
Eating too few calories can cause various problems:
- Deficiencies of cancer-fighting vitamins and other important nutrients such as calcium, which could result in osteoporosis or other conditions
- Slow metabolism, which could cause you to feel sluggish and cold, and to become constipated
- Slower thinking or “brain fog,” caused by not enough glucose getting to your brain
- Gallstones, which can occur when you’re on a very low-calorie diet (800 daily calories or fewer)
If you have concerns about your optimal calorie level, it’s best to talk with your doctor or other health professional to help you calculate a number that’s safe and effective for meeting your weight and health goals.
