If you’ve ever dieted properly through the education of a dietitian, a support group such as weight watchers or through an online app that calculates your calories for you such as myfitnesspal.com, you may already understand that there is a certain amount of calories you need to eat everyday in order to maintain your weight. There is also a certain amount of calories you need in order to fuel basic functions other than exercising such as digestion, hormonal activities, brain and neurological activity, blood circulation etc. For the average person, about 70% of the calories we burn goes to just keeping us alive and healthy. The rest we burn by doing everyday activities or exercise. We refer to this base caloric number as the resting metabolic rate (RMR)
You can calculate your RMR by going to this link below and entering your height and weight:
This calculates the amount of calories you need in order to maintain weight. If you cut out 300 to 500 of these calories per day or burn this amount through exercise, you can burn one to two lbs. a week. However, if you eat less than about 1200 calories a day for the average person, you may be taking away calories needed to keep you healthy. Of course, everyone is different and your doctor or dietitian should be able to determine what is best for you.
It’s important to note that the math used to calculate the average RMR for your height and weight is for most healthy people. It is not all together accurate. There are many people who’s RMRs are lower than this which means they have to eat even less and burn more calories in order to lose and maintain weight. These people will say they have “low metabolisms” and will say things like, “why is it some people can eat a sandwich and stay slim but if I so much as eat a slice of bread, I will gain weight?” This phenomenon usually happens to people who have dieted too often or incorrectly. They have restricted their caloric intake so much that their body slows down its use of energy. In order for them to maintain body weight, they have to eat even less than the average person.
A famous study done in 1994 by Donelly and colleagues illustrates this. Sedentary women were given only 520 kcal/day for a 12 week period. They were divided into a control group and different exercise groups. While they all lost weight, all of their RMR went down. The ones who exercised the most had the greatest decrease of RMR (down to 240 kcal/day, which represented a 13.5% decrease) This means that this group of women will now have to eat 240 less calories a day or burn 240 calories more with exercise just to maintain their weight than they did before this extreme diet.
This is the yo-yo dieter’s problem and why some people lose a lot of weight only to gain back more in the long run. This is also why most educated professionals will recommend reducing only 300-500 calories a day and no more than that. This is why we say that one to two pounds a week of weight loss is reasonable and why ethically minded professionals will not ask you to lose more weight or reduce more calories than this. But there is more.
After being starved for so long, the body will hold on to fat as a means of storage so when the starved subject does lose weight, much of it will be in the form of bone and muscle. This can lead to osteoporosis which is common in anorexic women. This also leads to more sports injuries and poor sports and exercise performance. So even though a person might lift weights, lack of enough protein and other nutrients fails to build the kind of muscle that raises our metabolism.
Furthermore, stress caused by over exercise and starvation can lead to amenorrhea or menstrual disorders which is a big problem in teenage athletic females. Without the proper hormonal balance needed from getting adequate nutritional intake, muscle and bone health weakens even more because the hormones are very important in regulating the functions that keep our bones and muscles strong.
Again, there are exceptions. If a person is severely obese, they may be able to lose more weight faster. But there comes a time when a person may keep losing fat, long after they have reached the state of having a healthy BMI. I have been in this situation. When I lost weight as a teen, I continued to do so and suffered from lowered metabolism and amenorrhea. This was partly due to incorrect education and body image. I made up for this later on in life, by getting educated and raising my metabolism by eating more healthy foods at the right times.
You can read more about my personal experiences with this in my blog:
As I study for my sports nutrition certification, I’m a saddened by the statistics of young female athletes who sabotage themselves with self starvation and it makes me wonder what we value as a society when our youth values deprivation over health. Realizing that I was once one of those unreported, malnourished kids makes me realize that these statistics are under reported and that there are more self starved people than that. I just want to say that if you are not menstruating properly, if you are not eating enough and wondering why you aren’t losing weight, if you are getting dizzy and nauseous during your workouts due to lack of nutrition, please get professional help. Beauty is more than just being skinny. Beauty comes from confidence, health and values that go beyond what we think we should look like. For this upcoming New Year, my wish is for people to aim for being stronger, more capable individuals who aren’t malnourished due to lack of education and poor body image.