science

I read Gary Taubs’ earlier book Good Calories Bad Calories a few weeks ago, I followed it up with his newer book Why We Get Fat: And What to Do About It. While it doesn’t have the same breadth of information as Good Calories it’s more clearly delivered and easier for non-technical-medial people to understand. Honestly I think it’s one of the better introductions to a ketogenic/high fat low carb diet that I’ve seen yet. Here’s some of the stuff I “took home” from the book.

We don’t get fat because we over eat. Meaning that overeating isn’t the cause of obesity, it’s an effect. If a room has a maximum occupancy of 20 people and the fire marshal gets upset and wants to know why it happened – you’re not going to say “well, it’s because more people came into the room than left.” Well duh, that’s what happened but that’s not the cause, the reason for the overcrowding. Rooms get overcrowded when more come in than leave and I get fat when I eat more than I burn; but that isn’t the cause.

20 calories a day. That’s all that’s needed to take someone from trim in their 20s to obese in their 60s. This is about how much you get by looking at a piece of cake wrong. If our calories in and calories out were regulated solely by willpower, maintaining the razor slim margin would be impossible. Instead our hunger and metabolism are controlled by a set of hormones and other factors. This goes completely contrary to what people like to think: that the obese would be thinner if they just stopped eating too much and got up and did some physical activity. It’s a character defect. They’re lazy and have no will power. Fortunately that entire line of thinking is wrong and it’s relatively easy to turn everything around.

When you eat sugars, starches or other stuff that breaks down into glucose (FYI: starch is just sugar that’s bound together in a polymer); your body reacts to the rising and damaging blood sugar levels by releasing insulin. In fact, your body actually starts releasing insulin before you start a meal; you only have to think of or smell food and your body will start to get ready and release insulin. Insulin does a bunch of things but of primary concern here is:

• It tells the cells in your body to stop burning fatty acids, we gotta get the blood sugar down.
• It tells your fat cells to store the free fatty acids that are circulating in your blood along with converting glucose in the blood into stored fat. Again, gotta get that blood sugar down.

So in the presence of insulin you will not burn fat, just glucose. Different cells are more or less reactive to insulin. Fat cells seem to react easily and don’t get tired of it, muscle cells and other cells tend to get resistant to the effects of insulin. When the cells don’t react to insulin at lower levels you’ll compensate by releasing more and more until your Islets of Langerhans can no longer keep up and you end up with type 2 diabetes. Oddly, your fat cells are still reacting to the insulin and dutifully storing energy away. It’s like your fat cells are acting without care for the rest of your cells (kinda like what cancer does). Anyhow, your cells still need energy; there’s no free fatty acids to consume so you end up with cellular starvation as your cells scream for something, anything to burn. If they can’t get anything then they will drop their activity to compensate. Just as you don’t get fat because you overeat, you don’t get fat because you are sedentary. Your desire or even ability to do physical activity drops in relation to the fuel available to your cells (besides the fat cells, because honey badger don’t care). If all the fuel your body can burn is glucose, you muscle cells don’t react to insulin because they are resistant and glucose is getting shoved into fat cells you will want to sit on a sofa and feed your starving cells. You get sedentary because you’re getting fat.

One thing that stuck with me: If you’re going to go to a huge dinner, what to you do to prepare so you can enjoy it as much as possible? Skip lunch and maybe even breakfast. Get some exercise, go for a walk. We call this working up an appetite for a reason. So to recap: to increase your hunger so you can eat more at a big feast you eat less and move more – which is precisely the advice given to lose weight? This is nuts! Exercise will make you hungry. If you burn 100 calories running, your body is going to figure out a way to replenish that missing fuel and hunger will move you to eat a little extra. There are many good reasons to exercise but exercising to try to  lose weight is insane.

The solution? cut the amount of insulin in your system. How do you do that? eat as few carbohydrates as possible.

You’ll have to battle your brain for a bit. Sugar does a really good job at stimulating the reward centers of the brain. Essentially you end up with an addiction to sugar, to pasta, to bread, to potatoes, to fruit. It’s more nuanced than that but when you stop eating sugars, refined flour and other easily digestible carbohydrates, you will feel withdrawals (though we call them cravings). Fortunately, the longer you go without these carbohydrates the cravings lessen. Your brain figures out how to run just fine on your stored fat as “ketone bodies” that your liver makes. Your cells aren’t inhibited from burning free fatty acids by overactive insulin so they increase activity. You feel the desire to get out and use up some of this extra energy. Your cells aren’t screaming for food so you don’t over eat. For that matter in most of the clinical trials of ketogenic diets, people lost more weight when they were told to eat how ever much they wanted, so long as it didn’t have carbohydrates. Eat more than you need? you probably won’t but if you do your body will compensate by upping activity. More bacon please.

If any of this sounds interesting and you want to learn the specifics instead of a general overview, be sure to check out the book: Why We Get Fat: And What to Do About It by Gary Taubes. It may even be at your local library. Looks like mine has 8 copies of the book and 1 copy of the audiobook available right now.