How to calculate your daily calorie and nutrient intake

Stop guessing and start calculating. This guide to calculating calorie needs includes numerous formulas for calculating your basal metabolic rate and advice on macronutrient intake.

The goal of this article is to provide you with guidelines that will help you determine not only how much food you should eat per day, but also how you should divide your three macronutrients - protein, carbohydrates and fats.

We will cover common terms and definitions in combination with formulas that can help you get on the right track. Before we start with this information, I would advise you to take a week or two to examine your current eating habits. Write down everything you eat and find out how many calories, how much protein, how many carbohydrates and how much fat you consume each day.

This will take some time and work, but it is necessary. If you don't know the portion sizes and the calorie and nutrient compositions of the foods you eat, then the information in the rest of this article won't matter or help.

Calorie consumption - from basal metabolic rate to total daily calorie consumption

The basal metabolic rate (BMR)

Basal metabolic rate is basically the amount of calories you would need each day if you didn't exercise all day and only needed minimal amounts of energy.

Basal metabolic rate is often confused with the amount of calories you should consume each day. This is not the case unless you are bedridden. The basal metabolic rate is a baseline value if you are not doing any physical activity.

NEAT

The term NEAT stands for non-exercise activity thermogenesis and describes the amount of calories you consume on a daily basis through non-planned exercise. NEAT includes things like walking around at work, going shopping or doing household activities. NEAT includes unplanned cardio or workouts with weights.

You typically have control over the calories consumed that are part of the NEAT. You can choose not to go shopping or not to clean the house, etc.

Exercise-induced thermogenesis (EAT)

Exercise-induced thermogenesis describes the amount of calories burned daily through planned exercise. Exercise-induced thermogenesis does not include activities such as going shopping or walking to work. Only your cardio training, your training with weights, Zumba training sessions, etc. are tolerated here.

The thermic effect of food (TEF)

The thermic effect of food is the amount of energy burned directly through food intake and digestion. The thermic effect of food will vary based on the fiber content and macronutrient composition of the meal.

The thermic effect of food is expressed as a percentage of the total calories of a meal. The thermic effect of food in a typical meal is around 15%. A protein-only meal can have a thermic effect of up to 25%, while the thermic effect of fat is typically less than 5%. Carbohydrates fall somewhere in the middle and can range from 5 to 25%. Fiber also has a high thermic effect.

Total daily calorie consumption

Total calorie expenditure is the combination of basal metabolic rate, NEAT, exercise-induced thermogenesis and the thermogenic effect of food. This is the total amount of calories you burn in a given day.

Total calorie expenditure = BMR + NEAT + EAT + TEF

Factors that influence basal metabolic rate and total daily calorie expenditure

Here are some of the most important factors that influence your total daily calorie expenditure:

• Testosterone levels - Long-term declining testosterone levels can lower your basal metabolic rate.
• Gender - Men generally have a higher basal metabolic rate than women.
• Health - If you are sick or injured, you typically don't move as much
• Puberty - If you are growing rapidly, you are likely to consume more calories than normal.
• Pregnancy - Pregnancy will increase your calorie consumption.
• Weight - The heavier you are, the more energy you will use to maintain your weight.
• Muscle tissue - Extra muscle tissue will increase the amount of calories you consume each day.
• Occupation - Do you have a desk job or are you constantly on your feet and moving around a lot?
• Exercise - Exercise obviously influences exercise-induced thermogenesis.
• Nutritional composition - The composition of your diet influences the thermogenic effect of food (TEF), which can increase or decrease your total daily calorie consumption.
• Unplanned physical activity - Are you a person who moves a lot or do you sit in front of the TV all evening?
• Body temperature - The higher your body temperature, the more energy you burn.
• Thyroid hormone levels - High thyroid hormone levels increase the basal metabolic rate.
• Caffeine and tobacco - Caffeine and tobacco consumption can increase your basal metabolic rate.
• Climate - If you work or sleep in an environment that is slightly warmer or cooler than normal, this will lead to higher energy expenditure.
• Stress - When you are stressed, this usually leads to an increase in energy expenditure.

Estimating your basal metabolic rate

Below are several methods used to determine your daily calorie needs.

Katch-McArdle BMR formula

The Katch-McArdle method is considered a reliable method for estimating your basal metabolic rate if you are relatively lean and have a fairly accurate estimate of your body fat percentage. The equation is:

Basal Metabolic Rate = 370 + (21.6 x lean body mass)

The fat-free body mass in kilos corresponds to your total weight minus your fat weight and is calculated using the formula

Fat-free body mass = weight - ((body fat percentage in % /100) * weight)

Cunningham formula for the basal metabolic rate

This is another formula that assumes you know your body fat percentage.

Basal metabolic rate = 500 + (22 x lean body mass)

Activity multiplier - calculating your total calorie consumption

Now that you have calculated your basal metabolic rate, you can multiply it by one of the following factors based on your activity level to get your total calorie consumption.

• Sedentary - Basal Metabolic Rate x 1.2: You don't get much exercise at work - desk job. After work, you spend the evening on the couch in front of the TV.
• Slightly active - basal metabolic rate x 1.375: Some daily activity plus some exercise 1 to 3 days a week.
• Moderately active - basal metabolic rate x 1.55: A reasonable amount of daily activity plus exercise 3 to 5 days a week.
• Very active - Basal metabolic rate x 1.725: You are very active and you exercise 6 to 7 days a week.
• Highly active - basal metabolic rate x 1.9: You are extremely active, including up to two training sessions per week and/or have a very physically demanding job.

These figures are only intended to give you a rough estimate. The first 2 weeks on a new calorie level may result in abnormal weight gain or weight loss as your body may either retain or excrete water due to changes in sodium and carbohydrate intake. Don't worry about the weight you gain or lose during the first 2 weeks of a bulking or definition phase as long as these changes are not abnormal.

After these 2 weeks, you should monitor your weight and make minor adjustments based on your goals.

Macronutrient intake

Now that you know how many calories you will be eating per day, it's time to determine the macronutrient composition of your diet. These macronutrients are protein, fat and carbohydrates.

• Protein - Contains 4 kcal per gram
• Fat - Contains 9 kcal per gram
• Carbohydrates - Contains 4 kcal per gram

Fat intake

Fat will not make you fat. Your body needs a reasonable amount of fat for overall health. Total fat intake should make up 20 to 35% of your total calorie intake.

If you feel you can function on higher amounts of carbohydrates, then a fat intake in the range of 20 to 25% of total calories could be an option. If you are struggling to eat enough food or if you react badly to carbohydrates, then a higher fat intake is recommended.

Protein intake

Protein intake can be a controversial topic. Some people claim that you should never eat more than 150 grams per day. Although the effectiveness of consuming more than 150 grams of protein per day for muscle building is questionable, there are certainly a number of other reasons to eat more than 150 grams.

A higher protein intake is perfectly safe and harmless if you do not suffer from kidney disease. If you are underweight or in a bulking phase and building muscle quickly, I recommend 200 to 250 grams of protein per day depending on your calorie consumption.

If you are eating a ton of calories per day, then you should up your protein intake to 250 grams. If your calorie intake is around 3000 kcal, then 200 to 220 grams of protein per day might be a good option. I would also like to note that if you have already built up a lot of lean muscle mass or are dieting, it may make sense to eat a little more protein than normal.

For exercisers who are building muscle at a moderate rate and doing some sort of slow and clean mass-building phase, 180 to 220 grams of protein per day is a good choice. Ultimately, you should adjust your protein intake based on your calorie needs and/or dietary preferences.

Women should consider a protein intake of 100 to 120 grams per day. If you are a younger and/or highly active woman, you should consume 120 grams of protein per day.

Carbohydrate intake

Now that you have determined your protein and fat intake, you can easily calculate your carbohydrate requirements by subtracting the amount of protein and fat calories from your total calorie intake and dividing the result by 4.

Keep in mind that you can adjust these values as needed based on what your body is telling you. I functioned better with more carbs when I was younger and function better with more fat in my forties.

Listening to your body is very important. Remind yourself to make small, incremental changes so that you can more easily assess your future needs.