What are the main source of calories?

Calories are a unit of energy found in food and drinks. The number of calories a food contains tells us how much potential energy it holds. The human body uses calories from food and drink to fuel everything we do, from thinking and breathing to exercising. Knowing the main sources of calories can help people make informed choices about what they eat and drink to meet their energy needs.

What are calories?

Calories are a measurement of the amount of energy in food and drinks. Specifically, a calorie is the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius. When we eat and drink, our bodies break down carbohydrates, proteins, fats, and alcohol from the food and drink into glucose and other molecules. This process of breaking down food and drink releases energy in the form of calories that our bodies use for functioning, growth, and physical activity.

The number of calories a food or drink contains tells us how much potential energy it provides. For nutrition labeling purposes, a calorie with a capital C (Calorie) is actually equivalent to 1 kilocalorie or 1000 calories with a lowercase c (calorie). The Calorie is the amount commonly used for nutrition labels.

Why do we need calories?

Calories are essential because they provide the energy that powers all of the body’s functions. Some key reasons we need calories include:

  • Fueling basic body functions like breathing, blood circulation, controlling body temperature, cell growth, brain function, and nerve function.
  • Enabling physical activity from fidgeting and maintaining posture to exercising and playing sports.
  • Providing energy for growth and development in children, teens, pregnant women, and breastfeeding mothers.
  • Maintaining a healthy body weight since extra calories are stored as fat which can be drawn on when calorie intake is lower.

Without adequate calories from food and beverages to meet daily energy needs, the body would be unable to function properly. Getting sufficient calories is essential for good health.

How many calories do people need?

Calorie needs differ from person to person depending on a variety of factors including age, sex, height, weight, activity level, and health status. The U.S. Department of Agriculture (USDA) provides estimated calorie requirements for different age groups:

Age Group Estimated Calorie Needs Per Day
Infants 0-6 months 500-600
Infants 7-12 months 600-700
Toddlers 1-2 years 1,000-1,200
Children 3-8 years 1,200-1,400
Girls 9-13 years 1,400-1,600
Boys 9-13 years 1,600-2,000
Girls 14-18 years 1,800-2,000
Boys 14-18 years 2,000-2,600
Women 19-30 years 1,800-2,400
Men 19-30 years 2,400-3,000
Women 31-50 years 1,800-2,200
Men 31-50 years 2,200-3,000
Women 51+ years 1,600-2,200
Men 51+ years 2,000-2,800

These estimated calorie requirements can vary based on a person’s individual energy needs. An active teenager or manual laborer, for instance, may require more calories than the average recommendation for their age and sex. Someone who is less active or trying to lose weight may require fewer calories. A doctor or registered dietitian can provide guidance on appropriate calorie intake for a certain individual.

Where do we get calories?

The three main sources of calories are carbohydrates, proteins, and fats. Alcohol also provides calories but is not considered an essential nutrient. Here is an overview of how many calories come from each of these sources:

Carbohydrates

Carbohydrates are the body’s main source of energy. Digested carbohydrates are broken down into glucose which circulates in the blood and provides fuel for cells throughout the body and brain. Carbohydrates should make up 45-65% of total daily calorie intake, according to USDA recommendations.

The main food sources of carbohydrates are:

  • Breads
  • Cereals
  • Rice
  • Pasta
  • Beans
  • Starchy vegetables like potatoes and corn
  • Fruits
  • Milk and yogurt
  • Sweets like cakes, cookies, and candy

One gram of carbohydrates contains approximately 4 Calories. Complex carbohydrates like whole grains provide longer lasting energy than simple carbs like sugar.

Protein

Protein is used primarily for growth, repair, and maintenance of body tissues and cells. Protein should provide 10-35% of total calories. The main sources of protein are:

  • Meat
  • Poultry
  • Fish
  • Eggs
  • Dairy products
  • Beans
  • Nuts
  • Soy foods like tofu

One gram of protein contains approximately 4 Calories.

Fats

While fats get a bad reputation, moderate amounts are essential for energy, absorbing vitamins, and protecting organs. Fat intake should range from 20-35% of total calories. Sources of fat include:

  • Oils like olive oil, canola oil, etc.
  • Butter
  • Animal fats in meat and poultry skin
  • Cheese
  • Nuts and seeds
  • Avocados
  • Salad dressings and vinaigrettes
  • Fried foods
  • Baked goods

One gram of fat contains 9 Calories, more than double the amount in carbohydrates and protein.

Alcohol

Alcoholic drinks like beer, wine, and liquor also provide calories, but they are not an essential nutrient. One gram of alcohol contains approximately 7 Calories. Moderation is key as excessive alcohol intake provides empty calories and can be harmful.

How to choose calorie sources

While carbohydrates, proteins, and fats are all needed in balance, the key is choosing nutrient-dense sources of these calories. Here are some tips for picking the best calorie sources:

  • Focus on whole foods over processed foods – Whole foods like fruits, vegetables, whole grains, low-fat dairy, lean protein and healthy fats provide the most nutrients for the calories.
  • Eat plenty of produce – Fruit and vegetables are great sources of vitamins, minerals and fiber with fewer calories than high fat foods.
  • Choose lean proteins – Select lean cuts of meat, skinless poultry, fish, beans, eggs and nuts for protein. Limit processed meats like bacon and sausage.
  • Include healthy fats – Incorporate olive oil, avocados, nuts, seeds and fatty fish which provide monounsaturated and polyunsaturated fats.
  • Read labels – Check the nutrition labels on packaged foods to be aware of calorie, fat, sodium and sugar content.
  • Watch portion sizes – Consuming too many calories from even healthy foods can lead to weight gain.
  • Hydrate with water – Water contains no calories yet helps fill you up and keeps the body functioning properly.

Focusing on a balanced diet full of vitamins, minerals, fiber, protein, and healthy fats will help ensure you meet your daily calorie needs while optimizing nutrition.

Conclusion

Knowing the number of calories and key sources in food helps us plan nutritious diets that meet our energy requirements. Carbohydrates, proteins and fats all provide essential calories, but choosing nutrient-dense options from each food group provides the best nutritional bang for the calorie buck. Following federal nutrition guidelines for daily calorie intakes along with eating plenty of fruits, vegetables, whole grains, lean proteins and healthy fats can supply the calories we need for good health.

Leave a Comment