Calories in food
- josephplatt1979
- Sep 8, 2021
- 8 min read
Updated: Jul 19, 2022
Calories in food
What are calories
Simply put, a calorie is a unit of energy just like a cm is a set unit.
Calories in food indicate the energy content of the food and beverages you eat and drink.
Human beings need energy to survive to breathe, move, pump blood and they acquire this energy from food. How the body produces energy from food varies enormously depending on the state of the food, how you chew it, how easy it is to digest and what you combine the food with. Understanding calories can help you make educated decisions about your diet and exercise.
Where do calories come from ?
There are three main sources of calories in food in the human diet and they come from the three macronutrients which are carbohydrates, fat, and protein.
Carbohydrates are the main source which provide four calories per gram. Carbs like rice, grains, and starches are a quick source of energy that breaks down easily.
Fat comes in second and offers more than twice as many calories, at nine calories per gram. Fat foods like cheese, avocados, and oils among those with the largest calorie count.
Protein is the third source, which delivers four calories per gram. Proteins come from meat, fish, plant, supplements and nuts.
Checking calories in food
Knowing the calories in food can help ensure you're not consuming too much. The calorie content of many shop-bought foods is stated on the packaging as part of the nutrition label. These labels include information on energy in kilojoules (kJ) and kilocalories (kcal), usually referred to as calories. They also include information on fat, carbohydrate, protein and salt.
Calories and kilojoules are both units of energy that are used to represent the amount of energy in a food. Calories and kJs both represent energy in the same way that centimetres and feet both measure height. The kilojoule (kJ) is an International system of units (SI) measurement whereas Calorie is a measure of energy using the metric system.
kcals or kilocalories are normally referred to simply as calories, however to be more precise, 1kcal is actually 1000 calories.
kjs or kilojoules are an alternative energy measurement used mostly by the scientific community. One kcal is equivalent to 4.2 kilojoules.
How Many Calories Should You Eat
You need to consume a certain number of calories each day for your metabolic processes to occur effectively and for your body to work properly. For men, this number is roughly 2500 calories per day. Women need roughly around 2000 calories per day.
As the recommended calorie intake guidelines suggest, the number of calories in food you need per day can vary based on a variety of factors. Among them are, Sex, Height, Weight, Age, and Activity level. To find out how many calories you will need can be found by putting your measurement into a calorie calculator. A weight/fat loss calculator allows you to estimate the exact number of calories that you need to lose weight and also tells how long it will take to reach your goal for weight loss.
All calories are not created equal
The general thought has always been that a calorie is a calorie and as long as you are expending more than you are taking in, you’ll lose weight. But many people who have struggled with weight loss have long felt that there was something wrong with that point of view. On paper we think calories in food are created equal, but the body treats them very differently. Our body handles different sources of nutrition differently, and different bodies will metabolize foods in different ways.
You may know that carbohydrates, fat, and protein have different caloric values per gram (4 calories per gram for carbohydrates and protein, and 9 calories per gram for fat), but they are also absorbed differently by the body. Protein is by far the most efficient, because it requires more energy to metabolize, which means that the body burns more calories when you eat protein compared to fat and carbs.
Some foods not only fail to leave you feeling full, but can actually have you craving more. Sugary, processed foods flood the pleasure centre of your brain with dopamine, which causes you to want more of that boost. Over time, a tolerance can build up, and your brain will require more sugar for your brain to win the same reward.
An example of this could be an avocado contains around 250 calories and a can of diet coke is less than 1 calorie. Is the healthy option the avocado or diet coke? If you were to make the decision based on the much-loved concept “eat less calories”, then logically you would choose diet coke over the avocado, but nutritionally speaking, this isn’t a good option.
This is because it's well-known that diet coke contains harmful artificial sweeteners that trigger sugar cravings as they’re up to 100 times sweeter than normal cane sugar, so your taste buds become desensitised to the taste of normal sweetness found in nature. This sets you off on the sugar rollercoaster, your insulin levels go haywire and your sugar cravings get worse.
Glucose and fructose are two simple sugars that are very common in our diets. Glucose can be metabolized by any tissue in your body; however, fructose must be converted in the liver before producing energy. Excess fructose is converted into cholesterol and triglycerides, increasing body fat and blood lipids. Calories from fructose are much more harmful than glucose, and should be avoided as part of an organic diet.
Fibre is a form of carbohydrate that contributes to satiety without contributing calories, because it is not absorbed into the body. Consequently, a 100-calorie high-fibre food will reduce appetite and subsequent eating more than a 100-calorie low-fibre food. Likewise, a person who increases their daily fibre consumption without making any conscious effort to eat less will wind up eating less anyway due to reduced appetite. Thus, a calorie inside a high-fibre food is not equal to a calorie inside a low-calorie food, another way in which a calorie is not a calorie.
Total Energy Expenditure
Your body weight reflects your energy balance. If you consume more calories than your body uses, you will gain weight. Likewise, you will lose weight if you consume fewer calories.
Body weight is not, however, an indicator of nutrient adequacy or the nutritional quality of the diet. The amount of energy expended by a person in a given time period which is usually daily is known as a metabolic rate.
There are three components to your metabolic rate: physical activity, resting metabolic rate, and the thermic effect of food.
Physical Activity - This is the most variable component of your daily energy expenditure. For most people, it accounts for approximately one-quarter of their total energy expenditure. It may be as little as 10 percent, however, in someone extremely inactive or bedridden and as much as 50 percent in athletes or heavy laborers.
Resting Metabolic Rate – This is a measurement of the number of calories that your body burns at rest. Resting metabolic rate is usually measured in the morning before you eat or exercise and after a full night of restful sleep. Resting metabolism is the energy required by your body to perform the most basic functions when your body is at rest. These essential functions include things like breathing, circulating blood or basic brain functions.
Thermic Effect of Food (TEF) - It takes energy to process the food you eat. Digestion of the food and the absorption, metabolism and storage of the nutrients account for approximately 10 percent of your total energy expenditure. The composition of your meal determines its TEF. Large meals have a greater TEF than small meals, and protein has a greater TEF than carbohydrate, which have a greater TEF than fat. In other words, eating protein “wastes” more calories than eating carbohydrates or fat. Thus, by increasing the protein content or your meal without increasing its calorie content, you can burn a few extra calories.
Calories and Exercise
When it comes to calories and exercise we count them, we cut them, we worry over them, we work hard burning them off and the thing is we can’t even see them. We all become obsessed about calories in food and weight loss and we all know that exercise is the best way to burn calories and burning calories is one of the best ways to manage your body’s weight. A good hour training session can easily burn 300-400 calories and this doesn’t mean you have to be doing hours of cardio or have to work up an excessive amount of sweat.
When you're active, your body uses more calories for energy and when you burn more calories than you consume, you lose weight. To lose weight, most people need to reduce the number of calories they consume and increase their physical activity. Getting to and staying at a healthy weight requires both regular physical activity and a healthy eating plan. Our eating plan should have calories consisting of healthy proteins, carbs and fat, as we need calories from food and drink to run our bodies the same way a car needs energy from fuel and your fridge needs electric energy to keep your food cold.
For some people, keeping track of calories in food can be helpful for promoting weight loss. People who log calories lose more weight and are more likely to keep the weight off in the long run. Knowing that you’re burning calories is different than being aware of the exact amount you’ve worked off. Calculating calories burned is helpful because it can make achieving your bodyweight goals easier. You can buy wearable activity trackers make calculating calories burned an effortless task and these can make it easier to achieve your calorie burnt goal.
Empty calories
Empty calories refer to the foods and drinks we consume that provide little or no nutritional benefit. Empty calories usually come in the form of added sugar or unhealthy fats. While proteins, complex carbs, and healthy fats work to fuel our bodies, empty calories are eaten more for enjoyment than for our health. These are foods that are often heavily processed with many additives and we don't require them in our diets so we can live without them. There is no health benefit to consuming foods that contain empty calories and they can actually have a negative impact on our health, leading to weight gain and chronic diseases, so it's best to limit or avoid empty calories. Empty calories in food and drinks include: soft drinks, alcohol, energy drinks, cordial, some white breads, biscuits, sweets, pastries, ice cream, condiments, fatty processed meats and many deep-fried takeaway foods.
The worst empty calories are the “hidden” ones you don’t know about, the ones you blissfully eat and drink without adding them to your note book. These hidden calories accumulate quickly and can lead to unexpected weight gain. Hidden calories leave you scratching your head, wondering why you put on weight. Hidden calories in many of today's most popular foods can derail even the most dedicated dieter striving for that new, healthier body this New Year. You may know about the 580-calorie Big Mac, but how about the 700-calorie cup of coffee and 590-calorie muffin? Or the 660-calorie salad with 51 grams fat? Those are just some examples of the worst offenders.
Best calorie approach
Having a healthy regimen of balanced meals and exercise will be the best approach to a healthy body and understanding calories can be a big help. Start by learning about your energy needs based on your age, sex, weight, and activity level. You can find what your needs will be through a calorie calculator, this gives you a great starting point.
Get information from food packaging to make educated decisions based on the labels. This will help you meet your daily calories in food requirements while building out your snacks and meals. Then, based on your weight management goals, you can decide how many calories you should be consuming compared to your baseline energy requirement.
Determine how many calories you can burn based on the physical activities you enjoy.
This will give you an idea of how long and how often you should exercise to achieve your weight management goals. No matter what your health and fitness goals are, you’re now armed to navigate the decisions more confidently.
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