JOHN YANG: According to the CDC, 1 in 5 American adults is living with obesity.

In the past few years, many have turned to weight loss drugs containing a hormone that slows digestion and helps with sustained weight loss.

It's called glucagon-like peptide-1 or GLP1.

Ali Rogin is back with her conversation with Dr. David Kessler, a former head of the FDA and himself a user of weight loss drugs.

In a new book, he advocates for their use, but says they shouldn't be seen as a quick and easy fix.

ALI ROGIN: Dr. Kessler, thank you so much for being here.

When you wrote this book, it was during a time when yourself were experiencing challenges with your weight.

What was happening in your life at that time?

DR. DAVID KESSLER, Author, "Diet, Drugs, and Dopamine": I had the privilege of co-leading Operation Warp Speed, an intense period for all of us, you know, through the pandemic.

And I found that I had gained 40 pounds over that period of time.

I was just, you know, in front of my computer working seven days a week, looked in the mirror and just didn't like myself and wanted to understand, you know, what was going on.

ALI ROGIN: One of your conclusions, I would say, is that you think GLP1s other weight loss medications are a good tool for some people to have in their arsenal, but that there need to better guardrails around it.

What is missing from the equation currently.

DAVID KESSLER: To understand these ultra-formulated foods, I mean, they're addictive.

The GLP-1 drugs, you know, can help tamp down that addiction.

But ultimately, you know, the important thing with this, these GLP-1 drugs is they really allow you to change your relationship with food.

We're living in this environment.

We took fat and sugar, fat and salt, fat, sugar and salt.

The perfect trifecta, you know, to keep us eating more and more, you know, put it on every corner, made it available 24, 7, made it socially acceptable to eat anytime.

Right.

So I mean, it's no surprise what happened to us.

ALI ROGIN: That's by design.

Right.

You lay out in the book the steps that food manufacturers take to make these foods basically addictive.

DAVID KESSLER: They will say they just have designed to give us foods that we want.

They will design foods to achieve this bliss point, but that those are the, you know, reward centers of the brain.

Those are the addictive centers of the brain.

So how do these drugs work?

They're no miracle pills.

Right?

ALI ROGIN: Right.

DAVID KESSLER: They are important tools.

They work by keeping food in your stomach longer, they work on the gut, they work on that part of the brain, but they make you know, feel full.

But the problem is that if you look, I mean, in this country, the average amount of time someone's on these drugs is maybe eight, nine months and then they're off it.

And these drugs only work while you're on them.

You gain back the weight.

So you know, what you have to do is you have to condition yourself, right, to change your relationship with food.

Otherwise, you know, the drug companies, the premise is to be on these for life.

So we have to learn how to use these drugs wisely.

But they are only one tool in a basket.

I mean, of tools that have to include nutrition therapy, physical activity, behavior changes.

Look, this isn't willpower.

This is biology.

But finally, you can do something to change your health.

But you shouldn't be afraid to ask for help.

You need somebody, well, physicians who are well trained, a dietitian.

I mean, you need a team to help you deal and overcome this addiction.

ALI ROGIN: And another part of the solution that you lay out is really a rethinking of food in the American diet and how we educate people on their food choices.

You talk in the book about the idea of a health populism movement now, of course, the Make America Healthy Again movement.

MAHA, this is a central pillar of what they're talking about is bringing healthy foods into schools, making them more available, educating people on food choices.

And of course they are led.

The figurehead is HHS Secretary Robert F. Kennedy.

What do you think of how that movement is addressing these issues and about the RFK effect more broadly?

DAVID KESSLER: The focus on these highly processed, I call them ultra-formulated foods is I think absolutely right.

I think we certainly struck a populist chord about concern about chronic disease.

The fact is, many of us in our senior years, I mean, are living, we're living longer, but you know, in more disabled because of cardiac renal diabetes.

So we have to focus on these chronic diseases.

I'm not sure the focus is exactly right.

I mean, there's, you know, they're focusing, however laudable, you know, on the colored dyes, on certain oils.

The real problem is this toxic fat, I mean, in our bodies.

And we have to reduce that metabolic chaos so we finally, finally have the tools to reclaim our health.

There should be nothing embarrassing or, you know, any shame that I need a little help, right?

But again, these drugs may have real adverse events.

They have to be managed wisely.

They are not the cure all one tool.

ALI ROGIN: The book is "Diet, Drugs and Dopamine: The New Science of Achieving a Healthy Weight."

Dr. David Kessler, thank you so much.

DAVID KESSLER: Thank you.