satiety: why people get fat

In the land of body weight, satiety is king.

‘Satiety’ is science-talk for feeling full. Satiety is caused by eating food. Information about the amount of food in your GI tract — like how much it’s stretching your stomach (‘gastric distension’) — is communicated from your gut to your brainstem and hypothalamus by peptide signals (with arbitrary and silly names) like cholecystokinin, glucagon-like peptide 1, and peptide YY.

If these signals are strong enough, voila! Your appetite is curbed.

Why is satiety so important to fat loss? Because we’re always getting hungry, we’re always eating, and we’re always getting full — one of the great circles of life.

And when it comes to satiety, wait for it…foods are not equal. Per calorie, some foods are far more filling than others. (Sources: 1, 2, 3, 4)

It’s hard to overstate the importance of this.

Let’s assume you’re not an ascetic monk who chooses a life of continual hunger pangs. In this case, you will generally, more or less, most of the time, often enough to count….eat until you feel somewhat full.

And if you consistently eat foods that are on the less-filling end of the spectrum, you will need to eat more of them — eat more total calories, in other words — to feel full.

So you will eat more total calories. (Because you’re not an ascetic monk who chooses a life of continual hunger pangs.)

And we all know what happens when you consistently eat more calories. You gain fat. And if you give it enough time — unless you’re a genetic luck-pot — you get fat.

While some people are genetically disposed to be fat, most people get fat because their regular diet contains less-filling foods.

And most people can get skinny by removing the less-filling foods from their regular diet and replacing them with more-filling foods (that still taste good; no ascetic monk-ing required).

The key to everything is to base your diet on more-filling foods.

But what foods are more filling, and which are less filling? Where is this elusive satiety spectrum?

It’s very simple. You don’t have to worry about any details. Just one, all-important, neon-bright dividing line:

processed foods vs. whole foods

Processed foods (definition to come) are generally much less filling than whole foods.

And because processed foods are less filling, when people have unlimited access to processed foods (like most of us do) they tend to eat more total calories. (Sources: 1, 2, 3)

Food processing is a science, an art, and an evolutionary novelty. It creates uber delicious foods that are aliens to our body’s satiety system — which evolved regulating whole-food diets.

For all its alleged complexity, the obesity epidemic is very simple. People eat too much processed food. A 2015 study found that 77% of the food Americans buy is processed — and that 61% is ‘highly processed.’

This is why 71% of us are overweight.

There are no mysterious forces at play — most of the food we eat is processed, so most of us are overweight. That’s it.

And in the cause lies the cure. Get in the habit of eliminating processed food from your regular diet. (The diet you follow most days of the week.)

But what exactly is ‘processed food,’ aside from obvious junk foods? Great question.
The term processed food isn’t in the dictionary, so here’s a useful definition:

processed food n : a food with an ingredients list longer than one item

Tune in next week.

Like this post? Read more.