The recommended daily calorie intake depends on several factors such as age, height, size, lifestyle, gender and overall health status. Globally, the average person’s minimum calorie requirement is approximately 1,800 kilocalories per day. It varies from 2,500–2,700 calories for men and 2,000–2,200 calories for women. However, the calorie consumption in developed countries and a growing number of emerging economies is higher than it used to be.
There are a number of factors that influence the number of calories that our body absorbs. How and when we eat is as important as how many calories we consume. The longer we chew our food, the more calories our body retains. Eating a big breakfast (700 calories) helps with weight reduction and maintenance. It also reduces the risk of diabetes, heart disease, and high cholesterol.
The source of calories is also highly important in terms of nutrition. A 500-calorie meal comprising fruits and vegetables is a lot healthier than a 500-calorie snack of chips or popcorn. A healthier meal also keeps us feeling fuller longer than high calorie junk food. A growing number of processed foods and beverages contain sugar. Most food labels do not list the quantities of added sugar and other details. Portion sizes in fast food joints and restaurants are also increasing. 20 years ago, the average cheeseburger in the USA had 333 calories. Today, each of these has over 600 calories. We will probably live longer if we eat 5 portions of fruit and vegetable per day.
Consuming carbohydrates increases insulin levels significantly because they enter the bloodstream rapidly in the form of glucose. Fats and protein do not have the same effect. Refined flour is a fast carbohydrate, while coarse oatmeal is slow. However, our body needs carbohydrates. The important thing to remember is that slow-release carbs are better for weight maintenance and overall health than fast carbs.
Ideal body weight depends on several factors like age, height, gender, bone density and muscle-fat ratio. All we need to do is roughly balance our calorie consumption with the calories we burn every day. We need calories to stay alive, even if we are not moving. 20% of the energy is used for metabolic processes in the brain. The remaining energy is needed in a resting state for respiration and blood circulation among other basal metabolic requirements.
The type of food we eat decides how efficiently the energy from respiration converts into physical (mechanical) power. Rather than calorie counting, we should focus more on eating a healthy and well balanced diet and being physically active.