The calorie calculator, also called the TDEE calculator, can help you in determining how many calories should you eat a day - or what your starting point is if you want to gain or lose weight. In this article, you will find not only the formulas our calorie counter uses, but also what kinds of food to eat to cut down your weight in a responsible way.

How many calories should I eat a day?

The recommended calorie intake, or TDEE (Total Daily Energy Expenditure), depends on many factors. They are quite easy to measure, and you (hopefully) already know some: your age, height, weight, and sex. There are others, like the level of your physical activity, which are more qualitative than quantitative, but it's still possible to measure and classify them. Other ones, like your metabolism or overall health, are very difficult to estimate. That's why, even though our calorie calculator takes into account most factors that influence the number of calories you need every day, it may not give results that are 100% accurate. Consider it more of a guideline than a rigorous directive.

For example, a 40-year-old man who has a physical job (equivalent to exercising six days a week), is the average American height (5 ft 9 in) and weight (194.7 lbs) should ingest 3567 calories a day. On the other hand, his daughter, an average 18-year-old girl (5 ft 4 in, 117 lbs) who exercises once a week only, needs only 1814 calories a day - over a thousand calories less than her father.

What are calories, exactly?

Calories are measures of energy. 1 calorie is equivalent to about 4.18 joules.

In nutrition, we actually deal with kilocalories (kcal), where 1 kcal is equal to a thousand of the "small" calories. As you could expect, 1 kcal = 4.18 kJ. (This article uses the term "calories" to describe kilocalories, like probably every other healthy diet article on the Internet).

Trying to lose weight? Eat eggs!

Eggs are a safe bet if you are on a diet or you just want to eat healthily. They are loaded with nutrients, contain no harmful additives, are relatively cheap, leave you feeling much fuller than other foods, and most importantly - are low in calories. A small egg (38 g) contains only 54 calories, while a medium sized one (44 g) has around 63 kcal. Inside a large egg (50 g) there is approximately 72 kcal, with the egg yolk containing around 55 calories and the remaining 17 kcal in the white. That's nothing! Especially if you are comparing it to the nutritional bomb you get with every single egg:

  • Proteins - the average egg contains ~6g of protein, mainly in the white part. Eggs are the source of complete protein - they contain all nine essential amino acids. What's more, they have the highest possible PDCAAS score, which means that the proteins in eggs are of the highest quality - they are present in fair proportions and easy to digest. Just to remind you - proteins are essential to our body. They are used for growth and repair but also to make enzymes, hormones, and antibodies.
  • Fats - one egg contains ~5 grams of fat (1.6 g of saturated), concentrated in the yolk. Most of those fats are the "good" ones, crucial in a balanced diet. Eggs are also a good source of healthy omega-3 fatty acids, which helps to protect your heart.
  • Cholesterol - eggs have been demonized in the past for their high cholesterol content. However, one medium egg has around 186 mg of cholesterol (62% of the recommended daily intake), and it contains both HDL ("good") and LDL("bad") cholesterol. To make it clear - our bodies need cholesterol, but in reasonable amounts. It's essential, in digestion, hormones production and muscle building, to name a few processes. One or two eggs a day is healthy for most of the people.
  • Vitamins and nutrients - eggs are an excellent source of vitamins (A, D, E, K, B12), iron, folate, selenium, but also lutein and zeaxanthin (antioxidants that reduce your risk of eye diseases) and choline (essential brain nutrient).

Do you now see that egg is one of Nature’s most nutrient-dense product? Don't forget to add a couple of eggs per week to your diet!

How our food calorie calculator works

The calorie calculator is based on the Mifflin - St Jeor equation. It allows you to find your Basal Metabolic Rate (BMR) - the amount of energy needed for your body to support only its basic vital functions. It differs for men and women:

BMR(men) = (10 * weight / 1kg + 6.25 * height / 1cm - 5 * age / 1 year + 5) kcal / day

BMR(women) = (10 * weight / 1kg + 6.25 * height / 1cm - 5 * age / 1 year - 161) kcal / day

After you calculate your BMR, you need to multiply it by a factor corresponding to your physical activity level:

  • Sedentary lifestyle (little or no exercise): 1.2
  • Slightly active lifestyle (light exercise or sports 1-2 days/week): 1.4
  • Moderately active lifestyle (moderate exercise or sports 2-3 days/week): 1.6
  • Very active lifestyle (hard exercise or sports 4-5 days/week): 1.75
  • Extra active lifestyle (very hard exercise, physical job or sports 6-7 days/week): 2.0
  • Professional athlete: 2.3

If you're not sure which activity level to choose, always go for a lower number. That's because most people overestimate how much they exercise, and if you want to lose weight, it's safer to assume that you are not as active as you'd expect yourself to be.

The result will be your TDEE - Total Daily Energy Expenditure. It is the daily calorie intake recommended for maintaining your current weight.

Calorie counter, TDEE, and losing weight

There are about 3500 calories stored in each pound of body fat (of course, this is the average amount). If you want to lose a pound a week, you can easily work out that you need to cut out 500 calories from your daily intake. Similarly, if you're going to gain weight, taking in an additional 500 calories a day will help you gain one pound per week. Remember that you can create this deficit either by eating less or increasing the TDEE by exercising.

You should never cut more than 1000 calories a day from your diet. As a rule of thumb, you should never go below 1200 calories a day if you're a woman and 1800 if you're a man.

Additionally, it's a good idea to divide the food calories between all meals in a healthy way. Our meal calorie calculator will surely be of help!

Before you start a rigorous diet, its a good idea to make sure whether you're really overweight or underweight. Our BMI calculator can be of use to you.

What to eat to lose weight

Calories are not the only thing we get from food. Eating 1000 calories in popcorn is definitely not the same as eating 1000 calories in fruit and vegetables. We also need a proper amount of macronutrients - carbohydrates, proteins, vitamins, iron, and others. If you want to lose weight, the best thing you can do is burn calories by exercising. You can also reduce the calorie intake, but you must be very careful and double-check whether you won't deprive your body of important substances.

The best idea is always to consult a specialist. A good plan is to find a dietitian, who will create a diet plan perfectly suited to your needs. In no case should you blindly follow any diet plan taken from an anonymous source. The list below provides some rules that can become an inspiration for your diet. They are taken from the Dietary Guidelines for Americans. If you are interested in the topic of healthy nutrition, you should give them a look - this document is full of valuable information.

  • All - or almost all - nutritional needs should be met from foods. In some cases, you may use supplements, but never settle for substituting your food with them.
  • Consume less than 10 percent of calories per day from added sugars.
  • Consume less than 10 percent of calories per day from saturated fats - use oils instead. They provide essential fatty acids and vitamin E.
  • Consume less than 2,300 milligrams (mg) per day of sodium. Its primary source is salt.
  • If you drink alcohol, don't exceed one drink per day for women and two drinks per day for men. Drink only if you are of legal drinking age.
  • Eat a lot of vegetables - don't leave out any of their subgroups. They are a source of fiber, potassium, vitamins A, C, K, E, B6, magnesium, iron and other nutrients.
  • Consume a lot of fruits, especially whole fruits - they provide, among many others, dietary fiber, potassium, and vitamin C.
  • Grains, at least half of which are whole grains, are also good for you.
  • Consume fat-free or low-fat dairy, including milk, yogurt, cheese, and/or fortified soy beverages. They are your primary source of calcium.
  • You should also consume a variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), nuts, seeds, and soy products. Meats, poultry, and seafood provide heme iron, which is more bioavailable than the non-heme iron found in plant sources.
  • It's always better to eat regular meals - try to plan them in advance and limit snacks to a minimum.
  • Remember that there are multiple ways to plan out your diet. A balanced vegetarian diet can be as nutritional for an adult as a meat-based diet.
Bogna Haponiuk and Hanna Pamuła, PhD candidate

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Calorie Calculator. How many calories should I eat?