Eric Ravussin, Ph.D.

It was a glass and steel structure southeast of Phoenix, in between Phoenix and Tucson. And eight people went into this biosphere. They had seven different biomes. There was desert, marsh, ocean, agriculture. How big was it? habitat. It was about three acres. And this was a rich Texan donor who wanted to do that basically for the sake of NASA to know how people can live in Otacy. Otacy.

It was a glass and steel structure southeast of Phoenix, in between Phoenix and Tucson. And eight people went into this biosphere. They had seven different biomes. There was desert, marsh, ocean, agriculture. How big was it? habitat. It was about three acres. And this was a rich Texan donor who wanted to do that basically for the sake of NASA to know how people can live in Otacy. Otacy.

Anyway, eight people entered this Biosphere 2. It's called 2 because Biosphere 1 was the Earth, and they decided to call it 2. Among these eight people, there was a faculty from UCLA, Roy Walford, who wrote the textbook with Rick Weindruck on caloric restriction.

Anyway, eight people entered this Biosphere 2. It's called 2 because Biosphere 1 was the Earth, and they decided to call it 2. Among these eight people, there was a faculty from UCLA, Roy Walford, who wrote the textbook with Rick Weindruck on caloric restriction.

And while they were in the biosphere and I was in Phoenix, Roy called me and said, we would like to do measurements of energy expenditure. Can we sneak in a Delta track or metabolic cart to measure our energy expenditure? And I said, oh, absolutely. And we can also measure your free living energy expenditure using doubly labeled water. And we did that anyway.

And while they were in the biosphere and I was in Phoenix, Roy called me and said, we would like to do measurements of energy expenditure. Can we sneak in a Delta track or metabolic cart to measure our energy expenditure? And I said, oh, absolutely. And we can also measure your free living energy expenditure using doubly labeled water. And we did that anyway.

from 1991 to 1993. Roy Warford was a physician of the group, but he was very, very interested in caloric restriction. What he didn't know, things went south. The agriculture, you know, they had pests, they couldn't control some of the insect, they had goats dying, and very quickly they didn't have enough food. And they lost on average 15% of their weight.

from 1991 to 1993. Roy Warford was a physician of the group, but he was very, very interested in caloric restriction. What he didn't know, things went south. The agriculture, you know, they had pests, they couldn't control some of the insect, they had goats dying, and very quickly they didn't have enough food. And they lost on average 15% of their weight.

None of them except one was maybe a BMI of 26 or 7. They were all between 20 and 25. And they became calorie restricted. And you had the guy who was writing the textbook on calorie restriction being the physician in the Biosphere 2.

None of them except one was maybe a BMI of 26 or 7. They were all between 20 and 25. And they became calorie restricted. And you had the guy who was writing the textbook on calorie restriction being the physician in the Biosphere 2.

We started to collaborate, and then when this RFA came out in the early 2000, a request for application grant from the NIA, immediately I called Roy and I said, Roy, we have done this study of energy expenditure, and they came and they stayed in the chamber, five of them, for one day, right when they came out of the biosphere.

We started to collaborate, and then when this RFA came out in the early 2000, a request for application grant from the NIA, immediately I called Roy and I said, Roy, we have done this study of energy expenditure, and they came and they stayed in the chamber, five of them, for one day, right when they came out of the biosphere.

And we need you as a consultant, and we want to write a grant which is going to be competitive. I'm not known in aging research. He accepted.

And we need you as a consultant, and we want to write a grant which is going to be competitive. I'm not known in aging research. He accepted.

It was low. I mean, very low because of their caloric restriction. We had to compare to a group of 72 people. I mean, it's all published, and I can send you some of the papers. They were about 200 calories below what you would expect for their weight and body composition.

It was low. I mean, very low because of their caloric restriction. We had to compare to a group of 72 people. I mean, it's all published, and I can send you some of the papers. They were about 200 calories below what you would expect for their weight and body composition.

Yeah. Three of them said, hey, we have been stuck for two years now in this biosphere. We don't want to go to a metabolic chamber in Phoenix. But the five who came, they came back six months later, and they regained their weight. They were normal weight, like at the entry, and we published this data.

Yeah. Three of them said, hey, we have been stuck for two years now in this biosphere. We don't want to go to a metabolic chamber in Phoenix. But the five who came, they came back six months later, and they regained their weight. They were normal weight, like at the entry, and we published this data.

Yeah, normalized. There's this argument with metabolic adaptation, how long does it last and these kind of things, but it was normal.

Yeah, normalized. There's this argument with metabolic adaptation, how long does it last and these kind of things, but it was normal.