How Food Choices Shape Memory, Cognition & Cravings | Dr. Scott Kanoski

Scott Kanoski (0:00)

When I started studying how diet impacts neurocognition and memory function, the first model we were studying was a high sugar model. The animals basically had ad-libitum access to a sugar solution about the same percentage of calories as a soft drink that we consume, and otherwise they had healthy food and water.

And with this model, the animals show hippocampal-dependent memory deficits when they're older, and these seem to persist later into life, even though they're not consuming the sugar anymore. There may be a role for the microbiome. There's some changes in the bacteria on the gut from the sugar model that may have a functional connection to the memory impairments. We've also looked at models where the animals are consuming like a total junk food diet. So we give them chocolate peanut butter cups, ruffled potato chips, rodent high-fat, high-sugar diet. They show these memory impairments at last, even after you switch them to a healthy diet.

Andrew Huberman (0:56)

Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life.

I'm Andrew Huberman and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. My guest today is Dr. Scott Kanoski. Dr. Scott Kanoski is a professor of human and evolutionary biology and neurobiology at the University of Southern California.

His lab studies how hunger and memory interact and how the mind and body impact appetite, body weight regulation, food craving and choice. Dr. Kanoski's lab also studies how different types of nutrients impact brain development and brain function later in life. Today, we discuss many topics, including GLP drugs, how they work, how they impact hunger, and how they impact things like longevity, cognition and drives in general. As you'll soon see, Dr. Scott Kanoski is an encyclopedia of useful information about how your brain and body control your relationship to food. And today, he shares that knowledge with you in a clear, unbiased, and in many cases, actionable way. It's a conversation about the interactions that occur between your brain and body involving hormones, neurotransmitters, your memory, and your experiences that I'm confident will powerfully inform how you think about food, your food choices, and nutrition in general. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford.

It is, however, part of my desire and effort to bring zero cost to consumer information about science and science-related tools to the general public. In keeping with that theme, today's episode does include sponsors. And now for my conversation with Dr. Scott Kanoski. Dr. Scott Kanoski, welcome.

Scott Kanoski (2:36)

Thank you. Pleasure to be here. Thanks for the invitation.

Andrew Huberman (2:39)

You work on a topic that people experience every day, which is hunger, feeding, and hopefully satiety. But we also have this obesity epidemic, which seems to be partially mitigated by the GLP drugs.

But there's a lot to this whole thing that we call hunger and food and appetite and weight and all of that. And today you'll educate us about all of it. But to start things off, because it's on everybody's mind, what are the GLPs? What is this glucagon-like peptide one in its natural form in the body? And then perhaps we can talk about the drugs that increase their levels, because either everyone's taking one of these now, coming off of one of these now, thinking about taking one, hates the idea that anyone's taking them, or has someone that they know is taking one. So, GLPs are here.

Scott Kanoski (3:31)

In its natural form, it's an in-cretin hormone. So, it's secreted from the distal intestines around food ingestion. So, there's a little bit of secretion before the meal actually starts. Then, there's additional secretion during the meal.

And this gets into circulation. There's also a source of GLP-1 that's produced in the brain, in the brain stem, nucleus tractus solitarius. There's a population of neurons that make GLP-1 and then extensively send GLP-1 message throughout the brain.

Andrew Huberman (4:03)

What do those do? Are they related to hunger as well?

Scott Kanoski (4:05)

The peripheral GLP-1 and the central GLP-1 have very similar effects. So, they're involved in hunger suppression. But, they seem to be operating independently. So, there doesn't seem to be a strong connection between the peripheral GLP-1 physiological system and the neurons that make GLP-1 in the brain. But, they do both have appetite suppressing effects.

Andrew Huberman (4:25)

But, presumably, they're doing other things as well, right?

Scott Kanoski (4:28)

Yeah.

They're helping to regulate blood glucose levels, to stimulate insulin secretion when there's high levels of glucose present in the blood. In fact, the first application of GLP-1-based drugs was for diabetes treatment, not for obesity. But, because they also suppress appetite and food intake, which leads to body weight loss, now they're probably more widely known for their weight loss capacity present day. But, they started off as diabetes treatment.