I think most people who struggle with their weight can relate to the war that goes on in their head about food.
I’ve written about this on many occasions. Most recently, I discussed the new wonder drugs of weight loss and their amazing ability to dial down the “food noise.”
As an “overweight” person—yes, even though I’m now in great shape, just like with any other addiction, I will always consider myself overweight—I hear that noise multiple times, each and every day. (It’s annoying!)
And I’m sure many of you can relate. So, let’s talk about it…
What causes obesity?
Talking about, and trying to determine, the root cause of obesity is important, as 42 percent of American adults struggle with it…
Is it genetic? Epigenetic? Cultural? Something else entirely? A combination of factors? WHAT?
I’ve been practicing weight management medicine my entire career and I still don’t have the answer. Plus, the medical community as a whole is ill-prepared to manage this growing epidemic.
Not to mention, studies have shown that those who successfully lose weight tend to gain back 50 percent of it within just two years.
And within five years? They gain back 80 percent.
As you can see, the situation is dire. And getting to the bottom of it is vital.
Well, an emerging theory suggests obesity is a disorder of the brain.
Of course, a few years ago, I may not have agreed with this. But with the new GLP-1 agonist drugs (like Ozempic and Mounjaro) working so well, science is looking at how they work on the reward and appetite centers in our brains.
Consider this: The machine that is our brain is constantly humming in the background, taking in subtle signals from our gut, hormones, and environment to determine hunger levels, how food makes us feel, and whether we’re taking in enough—or expending too much—energy.
In other words, we like to think we have control over what we eat, but just like with breathing, we can only control it for so long until the basics of physiology take over.
But what if that latter part is just broken in those struggling with obesity?
Is it the brain? Genes? MORE?
Right now, the studies linking the brain to obesity are a bit conflicting and confusing…
A 2011 Lancet study suggests that obese people lack receptors to the feel-good brain chemical dopamine. Therefore, they overeat in pursuit of pleasure they can’t feel.
On the contrary, a recent study (that’s not yet published) is finding people with obesity have too much dopamine, filling up those receptors so that the pleasure spike feels duller after eating.
In yet another study, Yale researchers tube-fed 500 calories of sugar or fat directly into the stomachs of two groups: 28 lean people and 30 people with obesity. And they observed brain activity using functional magnetic resonance imaging (fMRI).
Turns out, after the meal, about 30 regions of the brain were “quieter” in the lean people. That included parts of the striatum, which is associated with cravings. But in those with obesity, the brain barely responded at all.
Then there’s the genetic role…
Studies show genetics play a part in as much as 75 percent of an individual’s body mass index (BMI). Of course, many genes play a very small role in BMI. But about a dozen single genes—most of which influence brain function—are thought to have a large effect!
Here’s the twist…
Genetics alone can’t account for the expanding obesity rates in the U.S. over the last five decades. Simply put, our genes don’t change that quickly.
But do you know what HAS changed during the same time period?
You guessed it: our food supply.
I’ve run out of space for today, though. So, be sure to tune back in tomorrow as we continue this discussion.
Until next time,
“What Causes Obesity? More Science Points to the Brain.” WebMD, 12/15/2023. (webmd.com/obesity/news/20231215/what-causes-obesity-more-science-points-brain)