With more than two-thirds of Americans considered overweight or obese (meaning at least 30 percent above normal weight), many of our top health officials, organizations, and researchers are trying to unlock the secrets of metabolism in order to reverse this trend. The term metabolism simply means the process by which food is broken down in the body to produce energy and waste byproducts. For many years, the predominant thinking has been that a person who is overweight is simply eating more calories than their body is burning, thus storing the excess as fat tissue. This basic tenet of metabolism is now being challenged by a variety of theories; this article will explore some of the factors that current scientific studies indicate may impact metabolism or metabolic rate.
Most people are surprised to learn that their basal metabolic rate (BMR), which is the rate at which the body burns calories to sustain the basic functions without activity, represents a significant portion of their daily burn rate. For example, a 20-year-old male, 5’10” 155 lbs, would need approximately 1,600 calories per day in order to keep major organ systems working properly. What about the overweight person consuming 1,800 calories and going to the gym six days a week for two hours and seeing only a couple of pounds fall off in two months’ time? What is going on to slow the process of fat loss in this individual?
A check list of metabolism-lowering factors might include: chronic stress, eating habits, medications, plastics and smoking cessation. We’ll explore these in more detail.
Chronic Stress. When the body is stressed, it will increase production of cortisol, a fight or flight hormone. When this stress is chronic, the body is exposed to higher than normal circulating blood sugar and insulin levels (which turn on fat storage). Studies support that individuals getting less than 8 hours of sleep, were more prone to gain weight than those getting at least 8 hours. Mental, financial and even the stress of over-exercising can all contribute to this phenomenon.
Eating habits. It is well known from a landmark starvation study done during World War ii that eating significantly fewer calories than the body needs will decrease basal metabolic rate. In the Ansel Keys study, healthy young men consumed 45 percent of their daily caloric needs for several months, which resulted in a 40 percent decrease in metabolic rate. Dieters are very familiar with this pattern of losing significant amounts of weight only to watch it come back quickly once they go off their diet. Physiologically speaking, their lipogenesis (fat making) enzymes have doubled while their lipogenesis (fat breaking) enzymes have decreased 50 percent.
Medications it is well known that a number of prescription medications can cause weight gain; sometimes the mechanism is through increasing insulin resistance (meaning that the body produces more insulin than needed, turning on fat storage). Fluid retention is another side effect of some medications. Check with your pharmacist to find out if this is a probable side effect of any of your current medications.
Plastics. New animal research lends support to the idea that environmental exposure to certain chemicals in plastics during developing years may alter physiology, including metabolism. The chemicals are known as endocrine disrupters and can mimic natural hormones that regulate, for example, how many fat cells the body makes and how much is in them. In the past 30 years, thousands of chemicals have flooded the consumer market and some of them are showing up in low levels in people’s bodies. According to a recent U.S. centers for Disease control and Prevention study, about 93 percent of the U.S. population had bisphenol a, a chemical that can be found in canned goods and in hard, clear plastic containers such as baby bottles, in their bodies. Bruce Blumberg of the University of California, a key researcher in the field, has coined a new word for this type of chemical that can make you fat: “obesogens.” consumer and health advocates recommend that people avoid plastics that are commonly used in products such as cups, plates, takeout containers, baby bottles and reusable water bottles if they are stamped with recycling numbers 3, 6 and 7.
Smoking Cessation. The nicotine in cigarettes and smoke- less tobacco has a stimulating affect on metabolism. Many folks who have kicked the habit have found it difficult to avoid weight gain during the first 6-12 months after stopping. It is estimated that the average weight gain for someone who quits is 5-12 lbs. metabolic rate appears to drop 5-10 percent during this time so it is important to cut back on calorie intake some and increase physical activity if you want to avoid this pitfall.
Some helpful tips
Eat within an hour or two of waking up, followed by regular meals every 3-5 hours, getting the bulk of the days’ calories during the daytime when metabolism is the highest. If you exercise, eat a meal or snack within 30 minutes to maximize recovery and stimulate the metabolism. Reduce stress and get eight or more hours of sleep per night to lower cortisol levels. Don’t overly limit calories and lower your metabolic rate in the process. Instead, eat breakfast daily and a meal or snack every 3-5 hours with a balance of protein, carbohydrate and fat to even out insulin levels. Exercise will help your body utilize glucose better, reducing your risk for diabetes. It’s your body–so respect it.