So you think you’ll never get fat because you’ve always been skinny? Do you consider your body weight to be healthy because your bathroom scale says so? Well if you’re slacking off on healthy habits like exercise and regular physical activity, you’re sadly mistaken as you are indeed living a sedentary lifestyle. One of the most dangerous effects of a sedentary lifestyle is being fat, even when you’re skinny. In fact, excess fat puts you at increased risk for chronic illnesses such as heart disease, high cholesterol, high blood pressure, and type II diabetes, even if your body weight is “normal”. Before I give you the skinny on being fat, let me tell you a little bit about body weight in general.
Body weight is comprised of lean and fat mass which is collectively known as body composition. An ideal body composition is one that encompasses a lower percentage of fat mass and a higher percentage of lean mass relative to overall body weight (see the table below). As such, it is your body composition that determines whether or not you’re at an ideal body weight. Lean mass is the most important component of body weight because it’s primarily made up of muscle, a key determinant of overall metabolic rate (the rate at which you burn calories on a daily basis). Metabolic rate is also influenced by other non-modifiable factors (genetics, gender, age, and hormonal status) but, generally, decreases in muscle mass lead to reductions in overall metabolic rate. When metabolic rate is reduced, the tendency to gain fat mass is dramatically increased.
The two factors that have the most profound impact on your body composition are the amount of calories you consume and the amount you burn on a daily basis. A sensible, healthy diet involving moderately reduced calorie consumption coupled with regular cardiovascular exercise is the absolute best way for you to lose/manage your body fat. But it doesn’t stop there. You must also perform regular resistance (weight) training in order to preserve (or increase) your muscle mass. If you don’t use your muscles, you’ll lose mass. Thinner people who are sedentary tend to learn this the hard way…usually as thirty-somethings. In fact, sedentary people lose approximately 10 percent of lean mass for every decade after thirty.
Many people who were thin during childhood to early adulthood (up to 29) begin to notice that they’re gaining a significant amount of weight between the ages of 30 and 35, especially if they’re sedentary. This is mostly linked to initial declines in muscle mass and, consequently, reduced metabolic rate which occur in the thirties. During my previous life I had a client named Alina who was 36 years old and sedentary when I started working with her. Standing at 5’9, Alina’s body weight was pretty low (135 pounds) but she was extremely flabby and her abdominal fat was exaggerated. These were immediate red flags given that excess abdominal fat is linked to many chronic health problems. Alina’s primary goal was to lose her “muffin top”. During an initial consultation, she told me that she’d always been skinny because her metabolism was high but after her 35th birthday, she’d started developing belly fat and didn’t know why. Upon completing her fitness assessments, I discovered that Alina’s body fat percentage was 34. Indeed, Alina was fat and in her thirties she had begun to see the error of her sedentary ways. Her “high metabolism” was no longer on her side. Moreover, after performing her health screening, I discovered that a couple of other things were high: her blood pressure and cholesterol.
With declines in lean mass starting in the thirties it is much easier to become fat, even for a person who was skinny all of their life. The decline in lean mass with aging is inevitable; however, the rate at which this occurs is absolutely amenable to a behavioral intervention encompassing, sensible eating, cardiovascular exercise, and resistance training. This is especially important for women who tend to shy away from resistance training out of a fear of becoming too bulky. In general, the primary goal for people who are thin should be to increase muscle mass while moderately reducing fat mass.
In order to gain a clearer understanding of how fat you really are, consider having your body composition professionally assessed. These assessments can run anywhere from 20 to 200 dollars out of pocket, but it’s a healthy investment. Contact a local health club or the recreation department at a local college or university. Most colleges and universities offer body composition assessments at incredibly low prices or even free of charge if you participate in research.
Disclaimer: The information provided is for educational and informational purposes only and is not intended to diagnose, treat, cure or prevent any disease. Any reader who is concerned about his or her health should contact a physician for advice.
Before starting an exercise training program you should first make sure that exercise is safe for you. If you are under the age of 55 years and generally in good health, it is probably safe for you to exercise. However, if you are over 55 years of age and/or have any health problems, be sure to consult with your physician before starting an exercise training program.