When I started trying to eat healthy and control my weight, I found that counting calories was a very useful tool. It also happens to be quite easy to use now that I have a smart phone which is always with me. There are all kinds of apps that make calorie counting a snap to do. But, what are calories?
This item from Medical News Today gives a useful answer.
A calorie is a unit of energy. In nutrition and everyday language, calories refer to energy consumption through eating and drinking and energy usage through physical activity. For example, an apple may have 80 calories, while a one mile walk may use up about 100 calories.
There are two types of calories:
- A small calorie (symbol: cal) – 1 cal is the amount of energy required to raise one gram of water by one degree Celsius.
- A large calorie (symbol: Cal, kcal) – 1 Cal is the amount of energy required to raise one kilogram of water by one degree Celsius.1 large calorie (1 kcal) = 1,000 small calories.Most people associate calories just with food and drink, but anything that contains energy has calories. One ton of coal contains the equivalent in energy of 7,004,684,512 calories.The terms large calorie and small calorie can be confusing, and to add further confusion, are often mistakenly used interchangeably. This article focuses on calories associated with foods, drinks and human energy expenditure (our burning up of energy).According to Medilexicon’s medical dictionary, a Calorie is “a unit of heat content or energy. The amount of heat necessary to raise 1 g of water from 14.5-15.5°C (small calorie). Calorie is being replaced by joule, the SI unit equal to 0.239 calorie.”
The calories included in food labels are, in fact, kilocalories – units of 1,000 small calories. Therefore, a 250-calorie chocolate bar is actually 250,000 calories.
Calories and human health
The human body needs calories to survive, without energy our cells would die, our hearts and lungs would stop, and we would perish. We acquire this energy from food and drink.
If we consume just the number of calories our body needs each day, every day, we will probably enjoy happy and healthy lives. If our calorie consumption is too low or too high, we will eventually experience health complications.
The number of calories food contains tells us how much potential energy they possess. Below are the calorific values of the three main components of the food we eat:
- 1 gram of carbohydrates contains 4 calories
- 1 gram of protein contains 4 calories
- 1 gram of fat contains 9 calories.
Let’s look at where the calories in one cup of large eggs (243 grams) come from:
- Fat 24 grams.
24 x 9 = 216 calories.
- Protein 31 grams.
31 x 4 = 124 calories.
- Carbohydrate 2 grams.
2 x 4 = 8 calories
- 243 grams of raw egg contain 348 calories, of which 216 come from fat, 124 from protein and 8 from carbohydrate.
How many calories do we need each day?
Not everybody requires the same number of calories each day. Our ideal calorific consumption depends on several factors, including our overall general health, physical activity demands, sex, weight, height, and shape. A 6ft tall, 25-year-old professional soccer player needs many more calories each day than a 5ft 4 inch sedentary woman aged 75.
Health authorities around the world find it hard to agree on how many calories their citizens should ideally consume. The US government says the average man requires 2,700 calories per day and the average woman 2,200, while the NHS (National Health Service), UK, says it should be 2,500 and 2,000 respectively.
The FAO (Food and Agriculture Organization) of the United Nations says the average adult should consume no less than 1,800 calories per day.
A large breakfast helps control body weight – researchers from Tel Aviv University wrote in the journal Obesity that a big breakfast – one containing approximately 700 calories – is ideal for losing weight and lowering your risk of diabetes, heart disease, and high cholesterol.
Team leader, Prof. Daniela Jakubowicz stressed that when we eat our food matters as much as what we eat.
Fast food in American diets
Researchers from the CDC (Centers for Disease Control and Prevention) published a report in February, 2013, showing that 11.3% of people’s calories in the US come from fast foods.
Even though the figures are an improvement, nutritionists and health care professionals say it is still too high.
As people get older, they tend to get fewer of their daily calories from fast foods, the authors explained. Fast foods only made up 6% of seniors’ daily calorie intake.
They also found that non-Hispanic white people and Hispanic adults consume less fast food than black adults.
Many fast food restaurants serve meals that have calorie-counts much higher than the daily recommended amounts.
What are empty calories?
Empty calories, also known as discretionary calories are those we consume with very little nutritional value, they posses virtually no dietary fiber, amino acids, antioxidants, dietary minerals or vitamins.
According to ChooseMyPlate.gov, a part of the USDA, empty calories come mainly from solid fats and added sugars.
- Solid fats, such as beef fat, shortening and butter, are solid when at room temperature. Although solid fats exist naturally in many foods, they are commonly added during industrial food processing, as well as when certain foods are being prepared.
- Added sugars – these are calorific sweeteners that are added to foods and beverages during industrial processing. In the USA, the most common types of added sugars are sucrose and high-fructose corn syrup, which are mainly composed of about half fructose and half glucose.
Added sugars and solid fats are said make foods and drinks more enjoyable. They are added by food and beverage companies to boost sales. However, they also add many calories and are major contributors to the obesity epidemic.
Americans consume too many empty calories – Americans consume 336 calories per day from just sugary beverages, the CDC reported in 2011. According to the American Heart Association, sugar from drinks should not exceed 450 calories per week.
More than half of all Americans have at least one sugary drink each day. Approximately 5% of people aged two years or more in the USA consume at least 567 calories per day from sugary drinks, i.e. more than four cans daily.
Rachel Johnson, from the American Heart Association says:
“Sugar-sweetened beverages are the number one single source of calories in the American diet and account for about half of all added sugars that people consume.
Most Americans don’t have much room in their diets for a completely nutrient void beverage. One recent study showed that drinking more than one sugar-sweetened beverage a day increases your risk of high blood pressure.
It’s better if you can avoid them altogether and instead consume water, fat-free or 1% fat milk, 100% fruit juice and low-sodium vegetable juices.”
While some individuals are able to dismiss that chocolate bar in favor of a healthier snack, others are unlikely to be so composed. But according to a new study, this may be because the brains of some people are “hardwired” to crave foods high in fat and sugar.
Eating healthily when dining out can be a mammoth challenge; with all the delicious – albeit high-fat – foods to choose from, a salad is not quite so tempting. But it is not just the types of foods served that makes healthy eating difficult in restaurants; a new study found that more than 90% of meals from more than 120 restaurants assessed were served at portion sizes that exceeded calorie recommendations for a single meal.