Do weight loss drugs actually work? Here are 3 things to know

The day has finally arrived when a miracle drug promises to cleanse us of excess body fat. Is it time to celebrate? Maybe not, and folks who go the drug route need to understand the implications.

Do weight loss drugs work?

Survival is basic to our nature, and to survive we must have a constant supply of energy. This is why hunger is the strongest drive, and appetite is so difficult to harness and tame. The situation worsens when faced with ultra-processed foods loaded with chemicals that seduce our senses and drive appetite, taste, smell, and visual appeal, all things that keep us coming back for more.

The new weight loss drugs attack the problem at the source, mimicking the hormone glucagon-like peptide-1 (GLP-1) produced in the intestines which acts to target areas of the brain that control appetite.

Are they effective? You bet.

I’ve received emails and read many accounts from folks on the drugs who insist that even when confronted with their favorite foods, they take only a few bites, and are completely satisfied. Another factor that complements the lack of appetite is slowing emptying of the stomach. This creates a feeling of being full, even though you have eaten very little, reducing food intake even further. The drugs are known to possibly cause unpleasant gastrointestinal side effects, but I see this as a minor problem in the grand scheme of things.

Do I have to keep taking weight loss drugs forever?

Of all the warnings associated with these drugs, the one that stands out boldly is that once you start taking the drug and lose weight, you must continue for the rest of your life.

Why is this necessary? When you take a closer look, you realize that the drug creates the same circumstances as an extreme crash diet, but with the caveat of “built-in willpower."

In general, crash diets never work because they are too extreme and punishing, plus all you think about is food. Willpower keeps you going for a while, but soon you quit because it’s asking too much. But now, with the new drugs that slash appetite, you can starve yourself as you would on a crash diet, but without the need for strong willpower.

Lately, I’ve noticed that when weight loss drugs are talked about on TV, they add an important factor that was missing from earlier discussions of the drug when first introduced. To be sure, these drugs will help you lose some body fat, but they also take a huge toll on muscle mass.

This is one of several reasons why you must keep taking the drug forever. Let me explain.

Quick weight loss is not fat weight loss

You cannot lose body fat quickly. Think about it. Early man faced uncertainty every day when it came to eating, and often there was no food for prolonged periods. How did we survive back then? Over time we built up an energy reserve packed into body fat that got us through tough times. Body fat is an amazingly efficient energy storage device affording 3,500 calories (kcals) per pound. This means, all things being equal, the average size male would have to walk briskly 35 miles to lose one pound of fat. A smaller female would have to cover 44 miles at the same brisk pace.

Body fat helped ensure survival, and that’s why the body loves stored fat and surrenders it reluctantly. When food intake (energy) is greatly reduced, the body will respond by resetting the metabolic rate to a lower level. Losing muscle mass drops metabolic rate even lower, and when you combine both factors, you burn far fewer calories each day.

So, why does the body shed muscle? When food consumption and energy intake are too low (on the drug or a crash diet), the body worries there may be insufficient glucose available to meet the energy needs of the brain. In response, the body desperately searches for a source of glucose because it is the main fuel for the brain, and finds an unlikely source in the muscles.

Here’s how it works. Muscles are broken down to their base component, amino acids. The structure of some amino acids is similar to glucose, and these are taken to the liver and converted to glucose. Increased availability of glucose from muscle protein seems to solve the problem but at the expense of losing muscle mass. And you can lose muscle fast for two important reasons.

First, one pound of muscle yields only 700 usable calories, whereas one pound of fat yields 3,500. As a result, you can lose muscle five times faster than you lose fat. And second, losing muscle drops metabolic rate and you burn fewer calories per day.

Why do people gain weight back after dieting?

When you abandon a crash diet or quit taking a weight loss drug, you naturally go back to eating as usual. But your metabolic rate is low, which means you grossly overconsume calories. The result is a rapid fat gain. Eventually, when eating as you normally would, you should regain most of the muscle you lost, but not before gaining an excessive amount of fat.

The important message is: When it comes to weight loss drugs, you either sign on forever or risk gaining more weight back in the long run.

I realize I am a voice crying in the wilderness as these drugs are already in incredible demand, but the takeaway message should be this: Set a goal to lose as much body fat as possible while preserving your muscle mass. To do this you must keep your metabolic rate high by making only a subtle reduction in caloric intake. With this approach, it’s possible to lose about two pounds of fat per month, or twice that if you choose healthier foods and engage in lots of moderate daily exercise.

Reach Bryant Stamford, a professor of kinesiology and integrative physiology at Hanover College, at stamford@hanover.edu.

This article originally appeared on Louisville Courier Journal: Do weight loss drugs like Ozempic work? 3 things to know