Calories are units of energy that our body needs to carry out its essential functions such as breathing, circulating blood, and keeping our organs functioning properly. The number of calories you should eat depends on several factors, including your age, sex, height, weight, and activity level.
Calorie needs for men and women
On average, adult women need between 1600-2400 calories per day, while adult men need between 2000-3000 calories per day. However, these are just rough estimates, and your individual calorie needs may be different. The number of calories you need depends on various factors, including:
- Age: As we age, our metabolism slows down, so we need fewer calories.
- Sex: Men generally have more muscle mass and a higher metabolism than women, so they need more calories.
- Height: Taller people have more muscle mass and require more calories.
- Weight: Heavier people have more muscle mass and require more calories.
- Activity level: Active individuals require more calories than sedentary individuals.
Calculating your daily calorie needs
To calculate your daily calorie needs, you need to take into account your basal metabolic rate (BMR) and your physical activity level. Your BMR is the number of calories your body burns at rest, and it accounts for about 60-75% of your daily calorie needs.
To calculate your BMR, you can use the Harris-Benedict equation, which takes into account your sex, weight, height, and age:
For men: BMR = 88.4 + (13.4 x weight in kg) + (4.8 x height in cm) – (5.68 x age in years) For women: BMR = 447.6 + (9.25 x weight in kg) + (3.1 x height in cm) – (4.92 x age in years)
Once you have calculated your BMR, you can estimate your total daily calorie needs by multiplying your BMR by a factor that represents your activity level:
- Sedentary (little or no exercise): BMR x 1.2
- Lightly active (light exercise or sports 1-3 days a week): BMR x 1.375
- Moderately active (moderate exercise or sports 3-5 days a week): BMR x 1.55
- Very active (hard exercise or sports 6-7 days a week): BMR x 1.725
- Super active (very hard exercise or sports, physical job, or training twice a day): BMR x 1.9
For example, if you are a 35-year-old woman who is 5’6″ (168 cm) tall, weighs 150 pounds (68 kg), and exercises moderately three times a week, your daily calorie needs would be:
BMR = 447.6 + (9.25 x 68) + (3.1 x 168) – (4.92 x 35) = 1468.6 Total daily calorie needs = 1468.6 x 1.55 = 2276 calories per day.
Managing your calorie intake
Knowing how many calories you need to consume each day is the first step in managing your calorie intake. However, it’s also important to make sure you are getting the right balance of macronutrients – protein, carbohydrates, and fat – to support your health and fitness goals.
Protein: Protein is important for building and repairing muscle tissue and supporting immune function. Aim to consume at least 0.8 grams of protein per kilogram of body weight each day.