The Weekly Vlog

Top-Down Processing

Mar 13, 2024

A Bright Liner named Katie recently sent me a message with a great question. She wanted to know if, when you make Bright Line-compliant foods that would normally have sugar and flour—but you’re making them without—the brain has the ability to “fill in the blanks.” In other words, will the brain trick the body into creating the illusion of flour and sugar, so that it produces higher levels of insulin?

That’s exactly how it works. The brain does this all the time. It’s called top-down processing.

For all sensory perceptions, there are two main forms of processing: bottom-up and top-down. Bottom-up processing is what you might imagine: the brain takes in information—for example, through the retina, if it’s visual stimuli—and processes this to build the image from the bottom up.

But it turns out the brain has another way of working, where it gallops ahead and uses beliefs, expectations, and knowledge projected onto what it is perceiving. This is top-down processing. It’s where the brain makes assumptions and fills in the blanks, even if it doesn’t have a full picture in front of it.

But the brain isn’t always going to be right when it does this. So, for example, if someone mashes butternut squash and adds pumpkin pie spice to it, as far as the brain is concerned, it’s pumpkin pie. And it will respond accordingly as if you were actually eating pumpkin pie.

This is part of the reason why people don’t lose weight when they drink diet soda. The brain assumes you’re drinking sugar, and it releases insulin accordingly. Even with stevia or monk fruit, the total insulin released over a day is equivalent to what would be released if you’d consumed sucrose.

What this means for your Bright Line journey is that it’s prudent to be careful around look-alike foods.

It turns out that gaming the system, which people have been trying to do with diet soda for years, doesn’t work. You really do need to eat simple, nutritious whole foods, and not something that’s mocked up to resemble something else.

In Bright Line Eating, we’re not judging people who are, say, making cauliflower pizza without flour. But there’s science behind why this might not be a great idea, depending on your experience and Susceptibility Score.

If you’re a five or six on the Susceptibility Scale, and you’ve figured out a way to make cauliflower pizza part of your regular life, that’s fine. Even if you’re a ten, if it works for you, fine.

But if you’re eating cauliflower pizza and you’re not in your Bright body or are having a hard time keeping your lines Bright—this may be why.

Top-down processing is very powerful. It even results in heroin addicts overdosing with their typical dose, if they consume it in a different environment or without their knowledge. The conditioned tolerance response that the body launches when the usual sequence of events happens (two $20 bills in the hand … finding the dealer … getting the bindle of powder … cooking it up with a spoon…) literally results in the addict being able to absorb a larger dose of heroin without overdosing. In the absence of this sequence of events (e.g., shooting someone up while they are sleeping), the result can be death. On the same dose. Top-down processing is not to be taken lightly—it affects our physiology in powerful ways.

Click here to listen to this episode on Bright Line Living™ - The Official Bright Line Eating Podcast.

Susan Peirce Thompson, Ph.D. is a New York Times bestselling author and an expert in the psychology and neuroscience of eating.  Susan is the Founder and CEO of Bright Line Eating®, a scientifically grounded program that teaches you a simple process for getting your brain on board so you can finally find freedom from food.

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