When most of us think about calories we think about how to fatten a meal. In terms of diet, calories are the amount of nutrition a meal contains.
We’ll gain weight if we regularly take in more calories than we need. If we take in too little water, we will lose weight, fat, and eventually muscle mass. A calorie meaning is the amount of energy required to lift 1 gram (g) of water through 1 ° Celsius.
The type and amount of food we consume is what decides how many calories we consume. For those on a weight-loss diet, the amount of calories in a food is a deciding factor in choosing whether to consume it or not.
As the body absorbs energy differently during the day, how and what we eat will make a difference too. The use of energy from our body will depend on how involved we are, how effectively our body uses the energy, and on our age.
Women are expected to need between 1,600 and 2,400 calories a day, and men between 2,000 to 3,000 according to the Americans ‘Dietary Recommendations for 2015-2020. This depends however on their age, gender, height, lifestyle, overall health, and level of activity.
Fast facts on calorie intake and use
- Recommended calorie intake depends on factors such as age, size, height, sex, lifestyle, and overall general health.
- Recommended daily calorie intakes in the US are around 2,500 for men and 2,000 for women.
- Eating a big breakfast could help with weight reduction and maintenance.
- The brain uses around 20 percent of the energy used in the human body.
- Factors affecting ideal calorific intake include age, bone density, and muscle-fat ratio.
- A 500-calorie meal consisting of fruits and vegetables has more health benefits and will keep you feeling full for longer than a 500-calorie snack of pop
Recommended intake
The 2015-2020 Americans Dietary Guidelines suggest calorie intake ranging from 1,000 calories a day for a 2-year-old child to 3,200 for an active male aged 16 to 18.
As people get older they slow down their metabolic rate.
Which reduces their energy requirement. The average intake for women from age 19 to 25 is 2,000 calories a day, but after 51 years this falls to 1,600.
Burning calories
The human body needs energy to stay alive.
Around 20 percent of the energy we consume is used for metabolism in the brain. Much of the remainder is used in basal metabolism, the resources we use for functions such as blood circulation, digestion and respiration while in a resting state.
We need more energy to maintain a steady body temperature in a cold climate, as our metabolism rises to create more food. We need less water, in a warm climate.
For our skeletal muscles we do need mechanical energy, to maintain posture and to move about.
The metabolic cycle by which cells acquire energy by reacting oxygen with glucose to create carbon dioxide, water and energy is cell respiration.
How effectively breathing energy transforms into physical — or mechanical — power depends on the type of food consumed, the amount of physical energy, and what aerobic or anaerobic use of muscles is made of.
In other words, in order to fuel body functions like breathing and thinking, we need calories to sustain our posture, and to move about.
Tips
Here are some tips for burning energy and losing weight more effectively.
- Eat breakfast: A protein and healthy fat breakfast will keep you full for longer and help avoid daytime snacking.
- Eat daily meals: This will help you burn calories more efficiently and help avoid snacking in a wasteful way.
- Consider your “five-a-day”: fruits and vegetables can be a tasty snack, and can fill your meals out. These are rich in nutrients and protein, and low in fat and calories.
- Eat slow-: high- carbohydrates like legumes and healthy fats like avocado take longer to release sugar, so you’re not going to get hungry as easily as possible.
- Exercise: Exercise will help flush off excess calories, so you can feel good about it. It’s convenient for most people to do a brisk daily walk, and cost nothing. Challenge with a Pedometer. There are exercises for people using a wheelchair which can improve heart health and strength.
- Drink water: It is safe, it doesn’t have any calories and it will fill you up. Stop alcohol and soft drinks as these can easily contain too many calories. If you are looking for sweet drinks, select non-sweetened fruit juices, or get a juice maker.
- Eat more fiber: fiber that is found in fruits, vegetables and wholegrains will make you feel full and make you to digest well.
- Check the label: Some products have fats or sugars tucked away. “Ten percent less fat,” does not actually mean any less fat, so it doesn’t necessarily mean you should consume more of it or it’s even better. The mark will help you keep track whether you are counting calories.
- Using smaller plates: Evidence indicates portion sizes have risen over the past 3 decades and this may lead to obesity. Smaller plate use promotes smaller pieces.
- Slow down: Eat slowly and rest between courses or extra servings, because it may take your body 20 to 30 minutes to realize it is feeling full.
- Make a shopping list: Plan a week of healthful meals and snacks, list the ingredients you need, and when you go grocery shopping, stick to it.
- A little of what you fancy: Banning foods can lead to cravings and bingeing. Spoil yourself occasionally with a favorite treat, but in smaller amounts.
- Get enough sleep: Sleep loss affects the metabolism, and it has been linked to weight gain.
- Avoid eating 2 hours before bed: Eating within 2 hours of sleeping can interfere with sleep quality and promote weight gain.
Activities
Here are some examples of exercises that will help you burn in 30 minutes, and calories. The calculations are for an adult who weighs 125 pounds.
| Activity | Calories burned |
| Lifting weights | 90 |
| Aqua aerobics | 120 |
| Walking at 4.5 miles an hour | 150 |
| General swimming | 180 |
| Running at 6 miles an hour | 300 |
| Computer work | 41 |
| Sleeping | 19 |
Food choice
Holding calorie consumption under those limits does not guarantee a balanced diet, as different foods affect the body differently.
Insulin levels will increase substantially more after consuming carbohydrates (carbs) compared with eating fats or protein. Some carbs, especially in the form of sugar, or glucose, get into the bloodstream much faster than others.
Refined meal is a fast carb, whereas legumes are slower. For body weight management and overall health slow release carbs are better than fast carbs.
A 500-calorie meal of fish or beef, salad and some olive oil, accompanied by fruit, is healthier and stays off hunger longer than a 500-calorie buttered or toffee popcorn snack.
Daily needs
You need to know your basal metabolic rate and an activity factor to figure out how many calories you need.
Basal metabolic rate
One useful way of estimating BMR is the Mifflin-St. Jeor equation:
Men: 10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) + 5
Women: 10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) – 161
To calculate your BMR automatically, follow this link and enter your details into the calculator.
Activity factor
After calculating the BMR, multiply the result with an activity factor:
- Sedentary lifestyle: If you do very little or no exercise at all, your daily calorie requirement is BMR x 1.2.
- Slightly active lifestyle: If you do light exercise between one and three times a week, your daily calorie requirement is BMR x 1.375.
- Moderately active lifestyle: If you do moderate exercise three to five times a week, your daily calorie requirement is BMR x 1.55.
- Active lifestyle: If you do intensive exercise six to seven times per week, your daily calorie requirement is BMR x 1.725.
- Very active lifestyle: If you do very intensive exercise twice a day, with extra heavy workouts, your daily calorie requirement is BMR x 1.9.
It should offer a rough picture of the average intake of calories you need to hold your body weight where it is.
The conclusion is also not ideal, because the equation does not take into account the muscle-to-fat ratios. Even while resting, a very muscular person needs more calories.
Ideal body weight
As with requirements for calories, an ideal body weight depends on a variety of factors, including age, sex, bone density, muscle-fat ratio and height.
There are different ways of assessing an ideal weight.
Body mass index (BMI)
Body mass index (BMI) is one way of working out what a person should weigh. If you know your height and weight, you can use this calculator to find out your BMI.
| BMI | Definition |
| Below 18.5 | Underweight |
| 18.5 to 24.9 | Normal weight |
| 25-29.9 | Overweight |
| 30 or above | Obesity |
However, it does not take into account muscle mass.
Imagine a professional athlete weighing 200 pounds or 91 kilograms (kg) and standing 6 feet tall, or 1 meter (m) and 83 centimeters (cm). We may have the same BMI as a similarly high inactive person. The athlete is not overweight but more probably the inactive individual.
Waist-hip ratio
Researchers have found that there is a longer life expectancy for those people whose waist circumference is less than half their height.
People with a smaller waist to height were found to have a lower risk of obesity-related diabetes, cardiovascular disease, stroke and other health conditions.
An adult male who is 6 feet (183 cm) tall should have a waist that does not exceed 36 inches (91 cm).
An adult female who is 5 feet 4 inches (163 cm) tall should have a waist that does not exceed 32 inches (81 cm).
Measure halfway between the lower rib and the pelvic bone on the hip to determine the waiste.
When assessing a healthy weight this test can be more precise than BMI. However, it is limited because it does not accurately quantify the percentage of total body fat of an person, or the ratio of muscle to fat.
Diets
A large variety of diets claim to help people lose their body weight or hold it.
Some of these are healthy and reliable, and help people lose weight in the long run and keep it off. Some are hard to stick to, or easily put weight back on when the person starts following the diet.
See our article on the “Eight Most Common Diets” to find out more.
The rankings for these diets were based on how many things they were favorably listed, how common they were in general, and which ones earned the most positive reviews.
Eating a safe and well-balanced diet that you can maintain for more than 6 months is more critical than counting calories. It is equally necessary to be physically active and to align the calories expended each day with the energy used.
