For much of our history as a species, the threat of chronic food shortage and malnutrition has loomed over us.

Fortunately, due to global economies and remarkable advances in technology and agriculture, most of us living today in industrialized countries will probably never need to worry about starvation.

But ironically, we now must battle the consequences of excessive abundance of readily accessible food. All over the world, modern societies are confronting the challenge of obesity and diseases emanating from obesity.

An analysis of trends in adult body mass published in the Lancet puts the progression of this public health crisis into useful historical perspective: It revealed that the number of obese individuals has risen from 105 million in 1975 all the way to 641 million as of 2016. Over the past 40 years, we have gone from a world in which prevalence of underweight was more than double that of obesity, to a world in which people with obesity outnumber those who are underweight.

There has been vigorous debate on what aspects of our food supply are responsible for this relatively rapid shift in collective body composition. Recently, sugar has come under particularly fierce scrutiny, and understandably so. We do know that overconsumption of simple sugars can contribute to obesity and related diseases.

So what about fruit? Most types of fruit are naturally high in simple sugars, and we have essentially unlimited access to fruit year-round, even in the dead of winter. Could sweet fruit be a hidden contributor to the obesity epidemic?

And that brings me to our guest.

On this episode of humanOS Radio, Dan welcomes a familiar face back to the show - Stephan Guyenet. Stephan spent 12 years at the University of Washington researching the neuroscience underlying body fat regulation. There is perhaps nobody else, at least in our view, who has done more in recent years to help the general public understand the evidence related to energy regulation and weight control. This is why he is uniquely qualified to address the question of whether fruit actually does make you fat.

Last year, Stephan decided to answer the question of whether fruit was fattening in the most rigorous manner possible. Specifically, he wanted to look at the impact of whole, fresh fruit (as opposed to fruit juice, or other processed forms of fruit) on energy intake and adiposity. To that end, he conducted a systematic review of randomized controlled trials and prospective cohort studies, and that is what we have brought him on to discuss.

To learn about what he found, and what it means, check out the interview!