Asking “how many calories should I eat?” just begs the additional questions of “for what purpose?” and “Where do you live?” No, I’m not trying to be funny here, as you will see in a moment.
To lose weight, the answer to your question would be that you should eat 3500 calories less than what you are currently eating to lose a pound.
To gain weight, the answer to your question would be that you should eat 3500 calories more than what you are currently eating to gain a pound. But you should also build muscle, rather than simply “get fatter”.
To maintain weight, that depends on what your body measurements currently are, as well as your gender and activity level.
But the number of calories per day that you “should” eat, just for your continued health, depends on several things such as your age, weight, bone structure designation, height, gender, lifestyle, and overall general health. A physically active 6-foot male with a large bone structure who is 20 years old requires considerably more calories than a 5-foot sedentary woman with a small bone structure in her 70’s.
To make things even more complex, it also matters where you LIVE, because the recommended daily caloric requirements vary by country!
For example, the National Health Service (NHS) in the United Kingdom recommends that the average male adult needs approximately 2,500 calories per day to maintain his weight, while the average adult female needs 2,000. In the United States, the USDA recommends 2,700 calories per day for men and 2,200 for women.
Note that people in the UK are taller, on average, than Americans are, yet their recommend calories are lower. The NHS also focuses on healthy eating, and physical activity, and not in counting calories, while the US seems to be statistically-oriented with recommending so many calories or percentages from this group, and from that group, based on a certain number of calories consumed all day. So, note also that the overweight and obesity rates of both adults and children in the United States are considerably higher than those same rates in the United Kingdom.
Add the recommendations of the United Nation’s Food and Agriculture Organization (FAO), and you find that they suggest that the average person’s minimum calorie requirement per day, globally, should be approximately 1,800 calories! In the poorer countries, that number is really hard to meet as a minimum, and in others, it’s way too easy to consume way more than that without even giving it a second thought.
So, what, or whom, should you believe? Are the above numbers based on scientific research or on politics or economic gain?
To answer that question, consider that portion sizes in industrialized countries are not usually packaged in healthy amounts, and quite often the labeling is totally misleading. A soft drink container may look like it is only 1 serving, but check the label. It could be 2 to 3 servings, or more! The same is true of canned fruits, vegetables and other processed food combinations. Reading the label on an average size can of non-concentrated soup reveals it is 4.5 servings. However, we have been conditioned to think that 1 can = 1 serving because we have been trained to expect larger helpings.
In fact, the average sized cheeseburger in the United States was only 333 calories about 20 years ago. Now a cheeseburger is rather large item and has over 600 calories! Portion sizes in both elegant restaurants and fast food establishments have grown a lot larger than they were 20 years ago. This plays havoc with our brains, because we have learned portion sizes only by what is available and what we have been served in the past, and we are not at all educated about what a proper portion size really is. And when we have it explained to us, we are in shock, and think we will starve if we have to eat so little.
But simply counting calories and eating smaller portion sizes while not paying attention to what you are actually eating may be bad for your health. Insulin levels rise significantly higher after eating carbohydrates than after eating fats (no insulin rise at all) or proteins. Refined flour is a “fast carbohydrate” that gets into the bloodstream as glucose (a form of sugar) a lot faster than other foods and can actually make you fatter, while coarse oatmeal is a slow-release carbohydrate, which is better for weight control, insulin control, and overall health.
As you can probably guess, a 500-calorie meal consisting of a salad, with some olive oil, and fish or meat, followed by a piece of fruit (like apple, banana, peach or orange) is a much healthier choice and will keep you from being hungry for a longer period of time than a 500-calorie snack of buttered popcorn or a large onion bagel with cream cheese or egg.
OK, so if you are still determined to count calories, let’s go back to your question of “how many calories should I eat?” Well, approximately 20% of our body’s energy requirements are used for brain metabolism. The rest is used for basal metabolic requirements, such as being in a resting state, or for system functioning such blood circulation, breathing, cell respiration, body temperature regulation and digestion. Plus we need at least some of that energy for posture and moving around.
In other words, we NEED calories to stay alive, even if we are not moving, and definitely so that we can move around enough to get our next meal. But how many calories?
One way to answer your question is to point you to the Harris-Benedict principle, an equation that is used to estimate what the BMR (basal metabolic rate) and daily requirements are for a person. The BMR is multiplied by physical activity and the result is the recommended daily calorie intake to maintain the current weight.
This equation has limitations, for one thing, it uses metric measurements, so Americans will need to convert their weight to kilograms and their inches to centimeters. It does not take into account varying levels of muscle mass to fat mass ratios – a very muscular person needs more calories, even when resting. You can use this formula below, or you can search for a web-based calculator online that does the metric conversions for you.
Calculate your BMR
Multiply your current level of physical activity with your BMR
Sedentary lifestyle – if you do very little or no exercise at all
Slightly active lifestyle – light exercise between once and three times per week
Moderately active lifestyle – if you do moderate exercise three to five days per week
Active lifestyle – if you do intensive/heavy exercise six to seven times per week
Very active lifestyle – if you do very heavy/intensive exercise twice a day (extra heavy workouts)
Adjust the resulting “daily calorie requirement” number to either lose weight, gain weight, or just stay where you are.
But knowing how many calories you should eat does not give a good answer to next most common question of “How much should I weigh?” Your ideal weight is the one that your body was designed for in order to run efficiently and keep you healthy. You may think it is too fat, or too thin, but your body thinks it’s just right.
Just like trying to figure out how many calories you should eat each day, the ideal body weight depends on even more data factors, such as age, gender, bone density, muscle-to-fat ratio, and height.
BMI (Body Mass Index) is one way to figure out what you should weigh, but it does not take muscle mass into account. An Olympic runner and a couch potato may have the same BMI, but the Olympian is not overweight…the couch potato is the fatty.
Waist-to-hip ratio is a bit more accurate than BMI, but it does not properly measure your total body fat percentage, the muscle-to-fat ratio, and is limited.
Waist-to-height ratio is a new way of determining your ideal body weight and is the most accurate method available at present, but it has only been around since May, 2012, but is already said to be able to increase your life expectancy. The calculation is very simple:
Keep your waist circumference to less than half your height.
If you are a 6ft (183 cm) tall adult male, your waist should not exceed 36 inches (91 cm).
If you are a 5ft 4 inches (163 cm) tall adult female, your waist should not exceed 32 inches (81 cm)
So, just place your tape-measure half-way between your lower rib and your iliac crest (the the pelvic bone at the hip) to see where you stand with this measurement.