This year, my Thanksgiving dinner table conversation included weight loss efforts. My friends and family members reported their eating and aerobic exercise habits. No one mentioned resistance training.
Resistance strength training is essential for successful weight loss. To understand why, we must first understand anabolism and catabolism.
Anabolism vs. Catabolism
Catabolism is the process of breaking complex molecules into smaller ones to release energy as ATP, a chemical fuel for the body. ATP allows cellular functions, growth, and movement.
Anabolism builds complex models from simple ones through a process that requires ATP.
Anabolism and catabolism exist in a balance called homeostasis, which reflects the body’s metabolic condition.
Weight Loss Isn’t Just Superficial
Weight loss’s effects go beyond physical appearance. It improves almost every aspect of your health, including your health span (the number of years you enjoy optimum health).
To do that, we need to increase muscle mass and reduce fat tissue. How we lose weight determines what happens to those two components.
In traditional caloric restriction dieting, we consume fewer calories than our bodies metabolize, i.e., the body eats itself. When this happens, about 25% of weight loss comes from muscle and 75% from fat. For example, if you lose 10 pounds, 2.5 pounds will be muscle, and 7.5 pounds will be fat.
Fat cells are endocrinologically active. They skew our bodies metabolically in negative ways, and we want to get rid of them.
Muscle cells skew our bodies positively. Losing muscle puts some people at risk for sarcopenia — a lack of adequate muscle mass.
Muscle Mass and Metabolism
The body metabolizes (i.e., burns up as energy) 70–90% of its glucose in the muscle cells. The more muscle cells we have, the more adequate our glucose balance and quantity, and the healthier we are.
Muscle mass is how we:
- Preserve function, including our ability to move and perform tasks, and our ability to stay strong and balanced to reduce fall risk
- Preserve our quality of life
- Preserve and extend our life expectancy
As we age, we produce less hormones involved in muscle maintenance, such as human growth hormone and testosterone. People also tend to do less weight-bearing exercise as they age, so the muscles receive less stimulus to maintain their mass. And as we age, anabolic resistance (where it becomes harder for the muscles to build up from anabolic processes) makes it harder to maintain muscle mass.
Think of muscle mass as money in the bank. We invest our money early to ensure a comfortable retirement decades later. In the same way, lay down muscle mass when you’re young and energetic so it’s there to maintain later.
Balancing Anabolism and Catabolism
This brings us back to anabolism and catabolism.
You lose muscle mass if your body skews toward catabolism. Be exceptionally careful during that catabolic process to maintain muscle mass. Otherwise, you risk sarcopenia.
The Dangers of Weight-Loss Drugs
You’ve probably heard of a new, powerful class of weight-loss drugs, including Wegovy, Mounjaro, and Ozempic.
These GLP-1 receptor agonists (such as semaglutide and liraglutide) induce such strong catabolic states that they’re associated with 10–40% of weight loss as muscle mass. This happens because:
- Your body is strongly catabolic, breaking down lots of tissue.
- You’re making behavioral modifications. People often use these drugs in conjunction with dieting, markedly reducing caloric intake. However, calories provide the fuel your body needs to function. A person’s body can’t keep up with normal activity during rapid and extreme diet and weight loss, and muscles atrophy because of this reduced activity. With less energy for anabolic processes to maintain muscle, the balance shifts further to catabolism.
- Your appetite is suppressed. Patients taking GLP-1s crave carbohydrates and fat instead of protein, leading to muscle loss.
How to Optimize Anabolism and Catabolism to Lose Weight Safely
Prioritize losing the right weight: fat, not muscle mass. At Banner Peak Health, we don’t think about weight in isolation. Instead, we consider the relationship between anabolism and catabolism, and we use several techniques to facilitate fat loss and preserve muscle.
If you’re on a GLP-1 receptor agonist, you’ll complete an InBody composition scan every time you visit the office. We’ll measure your muscle mass vs. fat mass to ensure you lose less of the former and more of the latter.
We also help our patients increase their protein intake as a percentage of reduced total calories.
Healthy weight loss requires work — aerobic exercise, strength training, and protein consumption — and our physicians are here to help. Reach out today and tell us about your weight loss goals.
