food and nutrition


Metabolism

Question: Metabolism? In simple terms what is it? And really.. how does it have anything to do with weight gain? If we're all meant to eat the same amount then why does metabolism get in the way? I look like I have an eating disorder and yeah, supposedly I have a fast metabolism.

Answer: Metabolism is simply the process of turning food into energy (although it's actually not a simple process.) Metabolic rate (the rate at which they convert food into energy) can very from person-to-person, or even on a daily basis. Your activity levels, height, weight, gender, age, amount of lean mass, diet and even sleep can influence the rate at which you convert food into energy. Hormones or medical conditions (for example, hyper- or hypo-thyroidism) can also increase or decrease a person's metabolic rate. When it comes to metabolism, you body is doing either one of two things: breaking down tissue (catabolism) or building tissue (anabolism.) Catabolism happens when you are not eating enough calories to support the basic energy needs of your body. In this scenario, you will lose weight because the body doesn't have enough energy from food, and needs to tap stored sources like body fat or protein (in the form of muscle.) When you consume more calories than you need, your body will use them to build (anabolism) additional muscle, provided you are training your muscles. Or it will store the excess energy as fat, so that you can use it in the future should your calories decrease. Your comment that "we're all meant to eat the same amount" is actually not really accurate. Each person's calorie requirements are unique. The 2000 a day calorie estimates on the nutritional labels of the food you eat are just estimates for an average person with an average activity level. Depending on your own individual body composition and activity level, they can be somewhat higher or lower. However, realize that at a certain point, there is a floor. Most people, regardless of their metabolism, need to consume at least 1200 calories a day just to keep their bodies running. Althetes or very active people may need to consume two to three times that just to maintain their current weight. I've seen people (especially very thin women) who claim they just have a "fast metabolism." However, I've also noticed that they rarely eat -- sometimes they only eat one meal a day. This isn't a "fast metabolism" that is causing them to continue to lose weight or not gain any: it's the fact that they are starving themselves. They probably aren't even meeting their minimum calorie requirements. Likewise, I've seen obese or overweight individuals claim they have "slow metabolism" and then eat twice the daily calories they need for their size and weight. While their activity and eating habits may have temporarily changed their metabolic rate, the reason they gain weight is because they are eating MORE calories than they need. All things equal, a human being's base, resting metabolic rate only varies slightly from person-to-person (less than a 100 calorie difference.) Any variations above this are a product of their activity levels or body composition. Great question. Best of luck!


Related News and Products