Dr. Betty Murray explains why weight loss gets harder after 40: hormones shift, you lose 3 to 8 percent of muscle per decade, and stress raises cortisol, which triggers insulin resistance and belly fat storage.
Chapters
Foreign. Here's the first thing you got to know. Your hormone symphony is changing. And it changes a little bit from day to day and time to time, but it is definitely not the same hormone symphony that you had at 20 and 30. Progesterone is the first one to decline. That is your calming hormone. It's your relaxing and sleep hormone. It's what controls body temperature, to keep your core body temperature cooler so you can sleep through the night. So often you get insomnia, where you wake up and stay up in the middle of the night. And progesterone, as it declines, we're more likely to feel anxiety, ruminating thoughts, agitation. And so when your progesterone starts to decline, it also throws off cortisol, because cortisol's job is to also balance with progesterone. And when we have a declining level of progesterone, we have excessive cortisol relation to it to it, too. The other thing that can happen is if you're under a lot of psychological stress, cortisol is actually downstream from progesterone. So it is actually made from the metabolism of progesterone. And your body will do a thing called the cortisol or progesterone steel. And it basically says, hey, I don't need to make progesterone. I'm stressed out. I'm going to make cortisol. And what that does is it disrupts your sleep, disrupts your moods, and makes your body more likely to store fat at the same time. Now, number two, your metabolic engine is shrinking. You're losing about 3 to 8% of your muscle mass per decade, right? So for every muscle we lose, we use metabolic fire. Every pound of muscle will burn an extra 100 to 150 calories per day. So if I lose 3 to 8% of my muscle mass for each decade, I'm losing muscle mass, which means I'm not as metabolically sound. And this accelerates dramatically after 40 with the loss of estrogen. So muscles aren't just about strength. It's about glucose utilization, your blood sugar. And so if you don't have a really strong metabolic furnace and you don't have good muscle mass, you will be less capable of burning sugar from your bloodstream, and that's your major area. So more muscle means more metabolic strength, better glucose control, and better glucose disposal. When you can't dispose of glucose, you store it. And that we don't want. Now, next one, number three, your energy factories are aging, right? They're getting older. This is your mitochondria your powerhouse. This is the powerhouse of the cell. When the powerhouse of the cell becomes less efficient and we get less efficient at producing energy. So how does that show up? We get brain fog, fatigue, decision fatigue. We get feeling heavy in our body, not having the energy to get up and do the things you need to do every day, lack of motivation. And when they become less efficient. This is why your sleep can often make you feel tired even though you slept. It's because you're not producing enough energy. And this makes your tasks that you normally could handle seem very, very overwhelming. So your mitochondrial powerhouse is running on empty. I like to say it's kind of like you're driving a 1987 Yugo instead of a brand new Lamborghini, right? So powerhouses are really important. Now, the other thing that we see all the time, this is a biggie in every woman, but I'd say it's worse in this time period of life because we often have children that are grown or almost grown, empty nesting. We often are taking care of family members and other things. And we might be at the pinnacle of our career and other more stressful time periods. And your stress response in this time period is often stuck in overdrive. So everything that we do, all the caregiving, everything on our plate, adds to cortisol levels and adrenal output that is chronically elevated. When we have chronically elevated cortisol, our sleep is unrestorative. Our, our blood sugar control becomes less controlled and we become more insulin resistant. We lose muscle mass, we actively break down muscle, and it promotes fat storage, particularly around the midsection, which we don't want. And we can even see things like hair loss and increase in edema or storage of water. So you'll see like your fingers being more swollen or swelling around the eyes. And, and all of that excess stress leaves us feeling wired and tired, and it actively causes the breakdown of muscle and the storage of fat. So every hormone, your body gets an impact when cortisol has been elevated for a long time.
