Why do some people gain too much weight?

Treatment to reduce weight is different for different people. This handout is to help you to understand the different options.

What's in a word?

People differ in many ways, including their use of words. The word "overweight" means one thing to your fifteen old daughter and something else to my aunt. So in medicine we have words of our own to refer to specific medical problems. The word "obesity" was originally coined by physicians to describe a specific medical problem. Unfortunately physicians are people, and share our general cultural prejudice against people who are overweight. In the medical treatment of overweight people, however, we need to use words with an exact meaning like "obesity" so that we monitor use and side effects of diets, medications, and surgery with safety.

What is the medical meaning of the word "obesity?"

Obesity is an excess of total body fat. Weight is regulated by a complex set of biologic and environmental factors, not by a lack of willpower. The tendency to gain weight is genetic. Twins given up for adoption and raised in separate homes will have very similar weights years later. Before we talk about the metabolism and biochemistry of obesity, let's talk numbers.

There are several definitions of obesity.

BMI

The most common estimate of obesity is the body mass index (abbreviated here as BMI). You can calculate your BMI here. A BMI greater than 30 is considered by most people to define obesity, but read on for the exceptions.

Body composition

A more accurate method is to measure your percentage of body fat. Normally,a man should carry no more than 23% of his weight as fat, a woman no more than 27%. If you are overweight, your body has a higher "set-point" and you will do better to aim at a fat percentage between normal and the 40 to 50% you may carry currently carry. Our nurse can measure your body composition and tell you what a reasonable goal is for you. You can learn your body composition on our bioelectric impedance scale; this device will print out your weight (up to a 600 pound limit), your lean body weight, total body fat mass and percentage, and an estimate of a reasonable goal body weight were you to lose fat only.

One of our patients was losing weight fairly well until he "got stuck" at a BMI of around 30. He was a pretty muscular guy, and when we measured his body composition, he had only about 19% fat, which is well in the middle of the normal range. In his case, body composition measurement allowed him to stop trying to achieve the impossible. In his case, the BMI was dangerously inadequate as an estimate of his health and ideal weight.

Weight only

Another common definition of obesity is that a person weighs 20% or more over their ideal weight.

Waist to hip ratio

If you have more fat on the hips and thighs (shape like a pear), this is, on average, less risky than having more fat on the trunk than the hips (shape like an apple). You can measure around your waist at the navel and around the hips at their widest point. Divide the waist measurement by the hip measurement. In a man this ratio should be about .85 and in a woman between 0.7 and 0.75. If the ratio is higher, you need to keep reading.

More about BMI

Let's say a bit more about BMI, as it is so commonly used. A desirable body mass index is less than twenty three, but you aren't officially overweight unless your index is over 27. For a 5 foot 5 inch woman, this is a weight of 165 pounds, for a 5 foot 10 inch man, 190 pounds. This is the point at which insurance underwriters know that your risk of death starts to rise. Some authorities do not use the label "obese" until the person has a BMI greater than 30.

Between the ages of 55 and 74, the lowest mortality risk is in that group of people with a BMI between 25 and 30. Over the age of 75, excess weight is much less dangerous.

The big picture

Wherever you measure on the overweight scale, remember that a number is just a number. The important things in life are family, your spiritual life, your friends, your overall health, your ability to take care of yourself and to do your work-- let's keep this in perspective!

What we are after here is to reduce your risk of heart disease, diabetes, and so forth.

The risks of excess weight

Everyone knows that diabetes is common in people who are overweight for several years. Other consequences of obesity are:

• Increased rates of illness and death
• Reduced productivity and functioning in everyday tasks. Restrooms in airplanes, for example, aren't designed for the obese.
• Increased cost of healthcare. Difficulty buying health insurance.
• Social and economic discrimination- studies show obese people are discriminated against in admission to college, discriminated against in hiring, paid less at work, and have more difficulty renting housing.
• Psychological impairment due to poor self-image. Thirty-seven percent were depressed in one study.

Specific health problems include:

• Diabetes
• Colon cancer - If you look at people with a waist to hip ratio greater than .99, they have over three times the risk of developing colon cancer than do people with a waist to hip ratio less than .90.
• Osteoarthritis of the knees - risk increases by 10%with every 2 pound increase in weight
• Cancer in women- gallbladder, breast, cervix, endometrium of the uterus, and ovaries.
• Heart disease- and the conditions that lead to it, such as hypertension and arteriosclerosis
• Gout
• Increased cholesterol and triglycerides
• Stroke
• Menstrual and reproductive problems
• Gallbladder disease - gallstone rate is 3 per 1000 women per year with BMI less than 24, and 20 per 1000 women per year with BMI greater than 40.
• Increased risks from surgery
• Sleep apnea
• Congestive heart failure

Insurance companies make a living by estimating your risk of liv ing or dying. They know that people who are 30 to 40% above average weight are half again as likely to die in the next year as are people of average weight. People who are 100 pounds overweight, or twice their desirable weight, are eleven times more likely to die in the next year. People with a BMI of 50 have 12 times the death rate of those with a BMI of 25 to 35.[1]

On the bright side, the January 1, 1998 New England Journal of Medicine reported that the risks of excess weight fell as a person became older. If you're a male and make it to age 85, your appear to have no increased risk of death by being overweight. If you are a female, you need only live to age 75 to reduce your added risk due to overweight.

As you continue to read, I will tell you how to lose weight. There are several ways. One or another may be better for you. All will require something from you. Money, effort, time, a change in lifestyle, perhaps some risk of side effects. Look back at this list of the risks of being overweight when you wonder if it is worth it.

Physiology of obesity

We have a videotape to help you understand the following information. You may borrow it or view it at our office.

In 1994, workers at Rockefeller University in New York City discovered a gene called the ob gene (for obesity). When this gene is functioning properly it sends a signal to the brain to tell us to stop eating. In some people this gene is defective and the signal does not occur, causing them to eat more and gain weight. The signal is a hormone called leptin. When first this was discovered, they said "Aha, here is the answer to why people gain weight. They don't make enough leptin."

The big surprise was that people who are overweight are making more leptin than a normal person. In other words the signal is produced but the cells are not sensitive to it. The "stop eating" signal goes out but the cells that regulate appetite do not pick up the signal. Thus the person continues to eat and gains weight.

Is obesity a disease of the cell membrane?

The cells do not respond to the "stop eating" leptin signal because the cell membrane does not receive or process that signal. In people who are overweight, the cell membranes frequently do not process other cell signals as well. One of the signals the cell membrane may fail to process is the insulin signal. (If this persists the person will develop Type II diabetes.) Another signal they may fail to process is the thyroid signal.

So, what might be wrong with the cell membrane? The cell membrane, a fatty layer, separates the inside of the cell from the outside of the cell. These hormones require activation of a receptor to get through the cell membrane. Why are they not activating the receptor? In part this may be because the membranes become stiff. If the membranes are flexible as they normally are then the receptors are better able to move about and connect with the hormones. Often the membranes become stiff due to intake of partially hydrogenated vegetable oil. These are also called trans fatty acids. The FDA requires these to be the amount of these to be listed on labels if a threshold is exceeded, but they have set the threshold too high.

The book Fats That Heal, Fats That Kill by Udo Erasmus diagrams the manner by which trans fatty acids stiffen the membranes. It also shows how the essential fatty acids (the omega-3 and omega-6 fatty acids) operate to make the membrane more flexible.

So in order to improve the metabolic disturbance that results in obesity, type 2 diabetes and other disorders, one solution is to improve flexibility of the membranes through the use of essential fatty acids.

Thyroid hormone

Most people who are overweight do not lose much weight when hypothyroidism (low thyroid function) is treated. I think it is still important to be sure thyroid function is optimal. Our thyroid gland makes 4 different thyroid hormones, given the names of T4, T3, T2 and T1. The major output of the gland is in the form of T4. Once this enters the cell it is transformed into T3 which is the most active form of the hormone. No one knows why, but people with diabetes convert T4 to the active T3 slowly. Zinc and selenium are required for the body to convert T4 into T3. Lithium can interfere with this. I suggest that people trying to lose weight take 50 mg of zinc and about 500 mcg of selenium a day to insure adequate T4 to T3 conversion. I suggest that we always be sure that they have adequate thyroid function. If they are taking drugs like lithium that can interfere with that function, we need to take that into account. Essential fatty acids, by the way, stimulate the production of thyroid-stimulating hormone in the pituitary gland, which also optimizes thyroid function.

Allergy and weight gain

Finally, let's think about the immune system for a moment. When we think of our immune system being attacked by microorganisms we often think of the attack as coming from without, from the environment in which we live and from the people around us who may cough or have a cold. Actually the greater threat to us is from the inside. Two-thirds of our immune system lines the gastrointestinal tract to prevent yesterday's bacteria-laden and fermenting lunch from invading our body. A full discussion of this is beyond the scope of this paper. It is important for you to know that food allergy can play a role in poor health and can result in weight gain. Some people on a hypoallergenic diet find that they spontaneously lose weight without consciously restricting calories. We can advise you personally on optimal diet. Often we will have patients take a hypoallergenic food supplement to help them get adequate nutrition whilst diminishing allergic load.

Brain chemistry and obesity

We also know that brain chemistry can influence our health. Serotonin is a substance manufactured by the nerve cells in our brain that results in a sense of well-being. Serotonin levels are diminished in people with depression, obsessive-compulsive disorder, obesity, and several other conditions. In fact, fluoxetine (better known as Prozac®) in doses of sixty milligrams a day seems to help people lose weight. It also helps people with bulimia.

Weight control is for life

To continue with the main point here, obesity seems to have a genetic basis. Many overweight people gain weight at very young age, have a tendency to be overweight all of their life, and often have overweight relatives. So we often find that treatment of obesity is a lifelong requirement. If you have doubts about this, ask yourself whether this excess weight is threatening your health. (Or your job, or your marriage?) If you had diabetes or hypothyroidism, would you try to ignore it, or hope it would go away? Or think that a few months of intensive treatment would take care of it? No. Being overweight is the same.

Unless you are comfortable with the fact that excess weight is a situation requiring lifelong treatment, your chances of success are poor. Remember, benefits to treatment include not just better health, but can include an improved self image and more economic success.

Genetic make-up loads the gun: environment pulls the trigger

Your genes may determine whether you can become obese. It is your environment that determines whether you do become obese, and how obese you become.

How much weight should I lose?

Loss of just 5 to 10% of weight has been shown to reduce risk of complications such as high blood pressure, diabetes, and high cholesterol. Can you spell the word Realistic? Realism wins - buying lottery tickets or planning on getting back into that wedding dress are long shots. Yes, people do successfully lose more weight than that, and keep it off, but they don't do it on a whim or by accident.

You know that losing weight is not easy or you would not be reading this. You know that activity and wisdom in eating are important to losing weight. How you accomplish this depends on your own state of health, and I'd be glad to discuss it with you.

[1]Boisaubin, EV: Approach to obese patients[Topics in primary care medicine West J Med 1984 May; 140:794-797].

6/07

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