Scott Gibson - Why can't I lose weight ?

“Doctor, why can’t I lose weight?” This question, one of the most common asked of primary care physicians, would seem to have a simple answer. You eat too much. You exercise too little.

This response implies a failure of will, of determination, on the part of the patient. Yet the true answer is much deeper and more complicated.

The human body is designed to maintain weight. For most of human existence, the problem of weight has not been how to shed calories, but how to hold onto them.

In the past, food was often scarce, and starvation was more a threat than Type 2 diabetes. Those who could store calories internally had an improved chance of survival.

It is not surprising, then, that the greatest predictor of weight is heredity.

With one obese parent, the risk for obesity increases by 6.8 times. If both parents are obese, the risk rises 8.4 fold. Studies have shown that twins adopted into different households have weight patterns more like their genetic than their adoptive siblings. And identical twins have twice the obesity concordance with their identical than their fraternal siblings.

With obesity, heredity generally trumps environment.

New studies in the evolving field of epigenetics, where genes are turned on or off by our behavior, indicate that obesity genes can be switched on by overeating, and that mothers can transmit that “on” signal to their children. Those children run higher rates of obesity.

Essentially, you are what your grandmother ate.

Another impediment to voluntary control of weight exists in a host of hormones trying to lock us into our maximum weight. The gut produces more than 20 different hormones and peptides impacting our hunger and energy level.

A few hours after our last meal, these chemicals signal our brain it is time to eat. We get hungry. If we continue to forestall eating, hunger intensifies. Not only that, but the brain throws a wet blanket on our urge to move about, to exercise. Think of it as hormonal lethargy.

The persistence of the hormonal drive to eat over time was demonstrated in a study published in the New England Journal of Medicine in 2011. The researchers put a group of obese volunteers on a very low-calorie diet, resulting in loss of about 15 percent of their body weight over 10 weeks. Not surprisingly, they found that hunger hormones and self-reported hunger levels went up.

They then kept the study participants on a maintenance diet for a year, testing them periodically for hunger and hormone levels. The question was whether the body would adjust to this new, lower weight and assume a state of acceptance, with lower hunger hormone levels over time.

Instead, the researchers found, even after a year, both hunger and hormones remained perfidiously elevated from pre-weight-loss levels.

The body, it seems, strives to return us to our highest, not our optimal, weight. This drive is, no doubt, a heritage from an earlier time when optimal weight and highest weight were the same.

Only in the environment of unlimited calories we have today does the hunger mechanism confound our best interests.

This concept was borne out by a Swedish study reviewing obesity surgery versus dieting under medical supervision. The findings showed, at 10 years, the surgical group had lost 16 percent of body weight and the non-surgical group had gained 1.6 percent. An average change in weight of less than two percent over 10 years demonstrates how successfully the body maintains a stable weight.

What about diet plans? Which are the best? As it turns out, the differences among diets are slight.

Multiple studies over many years have found only small variations in effectiveness. The only consistent finding was that adherence to the diet, regardless of which diet, correlated well with weight loss.

The diet plan doesn’t really matter. Sticking to it does.

So, is there hope? Yes, within limits.

First, there are people who have achieved and maintained substantial weight loss without surgery. Such individuals attribute their success to diverse factors, from gritty self-determination to divine assistance, so it is hard to find a common theme. These successful few show it can be done, but clearly it is not easy.

Second, many people have very poor eating habits that can be fairly easily changed and may lead to weight loss. In recent years, the U.S. population has seen a slight dip in the prevalence of obesity, and some researchers point to the substitution of bottled water for sodas and juices as a likely cause. This is quite possible. Americans drink a frightening amount of their daily calories. A switch from Gatorade to water may substantially assist with weight loss.

Slashing the junk food/fast food/processed food habit also can be very helpful. Eating whole foods adds fiber and nutrients while subtracting calories. Mom was right. Eat your veggies.

Exercise is a vital part of any effort at improving health, but don’t count on it to drop your weight. The studies just don’t show it. You can, however, swap some fat for muscle, and the benefits to your health are substantial, regardless of whether you fit into your high school jeans.

The most effective strategy is preemptive — don’t become overweight in the first place. This truth is why so much emphasis is being placed on childhood obesity right now.

If children can get through puberty without becoming overweight, their chance of avoiding obesity as adults is greatly improved.

There appears to be progress in this area, as a recent study found a 40 percent drop in the prevalence of obesity in the past  decade among ages 2 to 5.

Weight loss is tough, frustrating and frequently discouraging. Many will not achieve the weight loss they seek. Yet almost everyone can do a better job of eating the right foods, eating in moderation and exercising. And these simple measures are the key to a longer, healthier life.


Guest writer Scott Gibson,  M.D., has been interested in the challenges of obesity for years. He earned his board certification in internal medicine from Providence Medical Center in 1987 and has practiced in McMinnville, his hometown, since 1989. He devotes his spare time to writing and photography.



Thank you for some very good information,I have watched with great trepidation family members struggle just to lose a few pounds , and then see huge weight gains.I hope this information will be of some help.

Scott Gibson

Glad it was helpful. Kind of depressing in ways, but at least people can understand the why of what they already know--weight loss is hard.

Ted E. Marr

It seems to me that most people either get thinner or heavier in older age. Is this really a fact?
Probably has a lot to do with one's eating habits and how active they are. Right?

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