Counting calories may help anyone wanting to safely lose or gain weight. However, it is also important to get calories from healthful sources and to sleep and exercise in the right amounts while moderating levels of stress.

Counting calories may seem overwhelming, but a range of tools, including apps and online calculators, can help.

In this article, we look into what calories are, how many to consume for healthful weight changes, and some of the best tools and tips for counting.

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Calories are a unit of measurement. They are a way to express an amount of energy.

People are generally most familiarTrusted Source with “big” calories, which convey the amount of energy in foods and drinks.

Caloric energy is vital in supporting life and health. It helps maintainTrusted Source key bodily functions, such as the functioning of cells.

The body converts calories from food, for example, into energy. It uses this energy immediately or stores it for later use, depending on its current needs.

There are many reasons to count calories. Broadly speaking, doing so allows a person to measure how much energy they are consuming per day.

If a person takes in more than their body uses, they generally begin to gain weight. If a person takes in less than their body requires, they generally start to lose weight.

If, over a prolonged period, foods rich in simple sugars are a primary source of excess calories, a person is at riskTrusted Source of:

People who are significantly increasing their activity levels need extra calories to account for those they are burning.

If a person consumes too few calories, they are at risk of:

  • weight gain caused by a decrease in cortisol production
  • heartbeat irregularities
  • weakening bones
  • the loss of mass in the kidneys, heart, and skeletal muscles
  • permanent organ damage
  • cardiac arrest

The number of calories that a person should consume depends on their:

  • weight
  • gender
  • age
  • height
  • activity levels

The National Institutes of Health (NIH)Trusted Source provide an online tool that calculates how many calories a person should be consuming to reach their goal weight.

The calculator also factors in the amount of time in which the person would like to reach this goal.

Several free apps available on iPhone and Android help people count calories, including:

  • MyFitnessPal, which tracks calories and macro- and micronutrients, and also has free recipes and health articles
  • MyNetDiary, which tracks exercise, steps, water intake, and caloric intake by meal
  • Lose It, which tracks weight, body fat, sleep, hydration, daily exercise, body measurements, and nutrients
  • My Diet Diary, which tracks calories, exercise, and hydration, and has forums for support
  • Fooducate, which helps track mood, exercise, sleep, and hunger, as well as calories

Most foods and drinks have labels that indicate portion sizes — in cups, ounces, grams, pieces, slices, or numbers.

Considering portions can helpTrusted Source with counting calories and maintaining a healthful weight.

For example, if the label on an ice cream tub shows that a portion measuring 2/3 cup has 230 calories, a person can measure out that amount and know exactly how many calories they are consuming. But if the person only has 115 calories left in that day’s allowance, they would consume only 1/3 cup to stay on track.

It helps to have an accurate set of cups, scales, and other measuring equipment handy.

Consuming more or fewer calories should never be the only consideration when setting weight or fitness goals. Sleep, stress, and activity levels all play a role in maintaining a healthful weight.

In addition, the source of calories — the quality and type of food or drink involved — can have a significant effect.

Every calorie converts to energy, but the same number of calories from different foods may have different effects.

For example, if a person consumes their daily allowance of calories from foods with plenty of added sugar and refined carbohydrates, this can raise their blood sugar levels and result in an increaseTrusted Source in fat storage.

Similarly, if foods rich in animal fats, particularly red meat, contribute a significant number of calories on a regular basis, this may increase the risk of certain cancers, such as esophageal cancer.

It is crucial to obtain calories from a healthful diet that contains fruits, vegetables, whole grains, and healthy sources of fats, such as nuts, avocados, and olive oil. These foods contain the nutrients that the body needs to function.

Refined sugar may be a particular concern, as a diet that contains an excess of it can lead to insulin spikes, causing fat cells to store calories. As these calories do not contain necessary nutrients, the body responds with a sensation of hunger.

Alcohol is likewise full of these “empty” calories, and it may contribute to unintentional weight gain.

The following strategies may help with counting calories:

  • keeping a food diary
  • using a calorie counter app
  • having a meal plan designed to provide the necessary number of calories
  • aiming for slow, steady changes to weight

Counting calories can help people reach and maintain their weight and fitness goals, as it involves tracking how much energy is going into the body each day.

Several apps and online tools can estimate how many daily calories a person needs to reach their goals and help track them day by day.

For anyone looking to make a change to their weight, it is crucial to also consider levels of stress and physical activity, plus the quality and amount of sleep. These factors all play a significant role.