Calorie Calculator

About This Calculator

This Calorie Calculator is based on several equations, and the results of the calculator are based on an estimated average. The Harris-Benedict Equation was one of the earliest equations used to calculate Basal Metabolic Rate (BMR), which is the amount of energy expended per day at rest. It was revised in 1984 to be more accurate and was used up until 1990, when the Mifflin-St Jeor Equation was introduced.

The Mifflin-St Jeor Equation also calculates BMR, and has been shown to be more accurate than the revised Harris-Benedict Equation. The Katch-McArdle Formula is slightly different in that it calculates resting daily energy expenditure (RDEE), which takes lean body mass into account. Of these equations, the Mifflin-St Jeor Equation is considered the most reliable formula for calculating BMR.

The value obtained from these equations is the estimated number of calories a person can consume in a day to maintain their body-weight, assuming they remain at rest. This value is multiplied by an activity factor (generally 1.2-1.9) dependent on a person's typical levels of exercise. 1 pound, or approximately 0.45 kg, equates to about 3,500 calories. As such, in order to lose 1 pound per week, it is recommended that 500 calories be shaved off the estimate of calories necessary for weight maintenance per day.

How Many Calories Do You Need?

Many people seek to lose weight, and often the easiest way to do this is to consume fewer calories each day. But how many calories does the body actually need in order to be healthy? This largely depends on the amount of physical activity a person performs each day, and regardless of this, is different for all people. There are many different factors involved, not all of which are well-understood or known.

Some factors that influence the number of calories a person needs to remain healthy include age, weight, height, sex, levels of physical activity, and overall general health. For example, a physically active 25-year-old male that is 6 feet in height requires considerably higher calorie intake than a 5-foot-tall, sedentary 70-year-old woman. Though it differs depending on age and activity level, adult males generally require 2,000-3,000 calories per day to maintain weight while adult females need around 1,600-2,400, according to the U.S. Department of Health.

The body does not require many calories to simply survive. However, consuming too few calories results in the body functioning poorly, since it will only use calories for functions essential to survival and ignore those necessary for general health and well-being. Harvard Health Publications suggests women get at least 1,200 calories and men get at least 1,500 calories a day unless supervised by doctors. As such, it is highly recommended that a person attempting to lose weight monitors their body's caloric necessities and adjusts them as necessary to maintain its nutritional needs.

Steps for Counting Calories

Calorie counting with the intent of losing weight can be broken down into a few general steps:

1. Determine your BMR: Use our calculator to find your maintenance calories. Remember that the values attained from these equations are approximations.
2. Determine your goals: Recall that 1 pound equates to approximately 3,500 calories. Reducing daily intake by 500 calories per day effectively results in a loss of 1 pound a week. It is generally not advisable to lose more than 2 pounds per week because it can have negative health effects. Learn more about healthy weight loss.
3. Choose a tracking method: Smartphone applications and digital journals facilitate tracking calories, macronutrients, and progress effectively.
4. Track progress: Take measurements over longer periods of time, such as weekly, as significant variations in weight can occur simply based on water intake.
5. Keep at it! Finding an approach that fits within your lifestyle ensures long-term sustainability.

Zigzag Calorie Cycling

Zigzag calorie cycling is a weight loss approach that aims to counteract the human body's natural adaptive tendencies. Counting and restricting calories is a viable method to lose weight, but over a period of time, it is possible for the body to adapt to the lower number of calories consumed, leading to a weight loss plateau.

Zigzag calorie cycling involves alternating the number of calories consumed on a given day. A person on a zigzag diet should have a combination of high-calorie and low-calorie days to meet the same overall weekly calorie target. This prevents the body's metabolism from adapting to a permanently slowed state and allows flexibility for social gatherings.

Calories: Different Kinds and Their Effects

The main sources of calories in a typical person's diet are carbohydrates, proteins, and fat, with alcohol also being a significant portion of calorie intake for many people, though ideally this should be limited since alcohol contains many empty calories. Some studies have shown that the calories displayed on nutrition labels and the calories actually consumed and retained can vary significantly.

Generally, foods that take more effort to chew - fruit, vegetables, lean meats, whole grains, and similar foods - require the body to burn more calories since more calories are required to digest them. It also results in the feeling of satiety for longer periods of time.

The "quality" of calories consumed is also important. There are different classifications of foods in terms of calories, including high-calorie foods, low-calorie foods, and empty calories. High-calorie foods are calorically dense, meaning that there are a high number of calories relative to serving size, while low-calorie foods have fewer calories relative to serving size.

Contraindications & When to Avoid Calorie Calculators

Mathematical formulas predict based on healthy statistical averages. However, certain medical conditions drastically alter how your body produces and utilizes energy. Do not strictly follow standard calorie calculators if you have:

• Diabetes or Severe Insulin Resistance: Your body may not process carbohydrates normally, meaning standard macronutrient breakdowns could trigger blood sugar spikes. Management requires specialized dietary tracking, not just calorie counting.
• Thyroid Disorders (Hypothyroidism/Hyperthyroidism): The Mifflin-St Jeor equation assumes a normal metabolic rate. Thyroid conditions can artificially slow or accelerate your BMR, making standard outputs highly inaccurate.
• Pregnancy and Breastfeeding: Caloric needs increase significantly and unpredictably. Trying to maintain a standard deficit can be dangerous.
• History of Eating Disorders: Strict tracking can trigger unhealthy psychological habits.

Formulas and Information

These are some of the most commonly used equations for estimating basal metabolic rate and resting energy needs.

Variable guide: W = body weight in kg, H = height in cm, A = age, and F = body fat proportion. Learn more about body composition measurements.

Calories in Common Foods

Fruit

Vegetables

Proteins

Common Meals/Snacks

Beverages/Dairy

* 1 cup = ~250 milliliters, 1 tablespoon = 14.2 grams.

1200, 1500, and 2000 Calorie Sample Meal Plans

These sample meal ideas show how different calorie targets can be spread across the day.

Calories Burned from Common Exercises

These examples show approximate calories burned per hour for different body weights.

Energy from Common Food Components