Appetite, Growth

[SS-FZ]

Mark,

Do you think that appetite is something that is regulated by your body for health? i.e. your body telling you it does not need more food because that would cause problems for you?

You notice some people have no problem 'filling out' while growing up, they get a natural spike in appetite an gain weight rapidly. Others seem to struggle -- they end up skinny.

Could this be a result of eating habits that have formed for the two individuals? or is it the body telling itself that its not comfortable carrying the extra weight?

I think weight gain happens naturally as a result of barbell training, but it happens very slowly. This makes sense, since muscles need to be repaired and reinforced so that next time what caused the micro tears in the muscle bellies does not do so as easily now.

But if we're interested in speeding up the process, we need to intervene and 'artificially' spike appetite. Why do we need to do this? Why can't the body understand that if more food means better, faster recovery, why doesn't it significantly increase its appetite naturally?

Lastly, when appetite is left unsupervised, I've noticed that it always tends to drift back to where it was previously (i.e. fat people on a diet get back to being fat, skinny guys who've gained weight lose weight)

back to the question:

Appetite: Health measures taken by the body or eating habits formed?

[Robert Santana]

Mark,

Do you think that appetite is something that is regulated by your body for health? i.e. your body telling you it does not need more food because that would cause problems for you?

You notice some people have no problem 'filling out' while growing up, they get a natural spike in appetite an gain weight rapidly. Others seem to struggle -- they end up skinny.

Could this be a result of eating habits that have formed for the two individuals? or is it the body telling itself that its not comfortable carrying the extra weight?

I think weight gain happens naturally as a result of barbell training, but it happens very slowly. This makes sense, since muscles need to be repaired and reinforced so that next time what caused the micro tears in the muscle bellies does not do so as easily now.

But if we're interested in speeding up the process, we need to intervene and 'artificially' spike appetite. Why do we need to do this? Why can't the body understand that if more food means better, faster recovery, why doesn't it significantly increase its appetite naturally?

Lastly, when appetite is left unsupervised, I've noticed that it always tends to drift back to where it was previously (i.e. fat people on a diet get back to being fat, skinny guys who've gained weight lose weight)

back to the question:

Appetite: Health measures taken by the body or eating habits formed?

Great question! There are certainly mechanisms in place that regulate appetite and what is more interesting is that research has found that individuals who "weight cycle" (meaning gain and lose weight) disrupt some of them. Specifically hunger hormones tend to get upregulated after periods of dieting, resting metabolic rate decreases via adaptive thermogenesis etc. Even more interesting is in the case of the person who is naturally thin and struggles to gain weight. Some individuals have more brown adipose tissue, which contains higher levels of uncoupling proteins, which cause more energy to be lost as heat. These people tend to be naturally thin no matter how much they eat and also tend to "run hot," meaning that they feel hot very easily. That's the biology half of it. We all have homestatic set points for most things and that set point is going to vary from individual to individual. Some of this can be altered to an extent through training, diet etc but generally we are always going to naturally gravitate back to our physiological 'norm.'

[thras]

How come everybody’s set points went upwards a few dozen pounds post-1970? My own family got fat like a light switch turning on.

[Robert Santana]

How come everybody’s set points went upwards a few dozen pounds post-1970? My own family got fat like a light switch turning on.

We don't really have an exact answer to this but I venture to speculate that if we had measures of actual dietary intake we'd have a better sense of why this is.

[crookedfinger]

We don't really have an exact answer to this but I venture to speculate that if we had measures of actual dietary intake we'd have a better sense of why this is.

Questions regarding set points:
Are they tied specifically to body weight or body fat percentage? Do we know?

Do we have a collective data point on what type of fluctuation from a percentage is tolerable for the body before other metabolic regulators kick in?

[Robert Santana]

Questions regarding set points:
Are they tied specifically to body weight or body fat percentage? Do we know?

Do we have a collective data point on what type of fluctuation from a percentage is tolerable for the body before other metabolic regulators kick in?

I'd say its tied to fat mass since that is a direct metric of our stored energy depots. At a certain point our body recognizes that additional fat loss threatens survival. I'm not sure that we have a collective data point but there are plenty of papers out there on weight cycling and fat loss plateaus that show a return to baseline and sometimes above baseline. There was a paper in the 1970s that looked fat cell size and fat cell number in overweight and obese women losing weight. Not the tightest controlled trial but they found that the fat cells seemed to hit a wall at around ~0.40 mcg per cell, which was the proposed minimum fat cell size. Again, the diet was not controlled and they were simply instructed to "lose weight until they couldn't anymore" then return to the lab. Interesting nonetheless.

[SS-FZ]

Questions regarding set points:
Are they tied specifically to body weight or body fat percentage? Do we know?

Do we have a collective data point on what type of fluctuation from a percentage is tolerable for the body before other metabolic regulators kick in?

My guess would be body fat.

I suppose if it isn't body-fat then it's muscle mass, and why would the body have a reason to get rid of muscle mass -- something that's useful for survival?

I would think that bulking/cutting works because of this fact, body gets rid of fat quickly (returning to a physiological 'norm') -- especially if you had to 'forcefully' eat to get that way, but maintains the muscle because that's important.

As for the tolerable fluctuation for an increase in weight (body-fat), I'm not sure.

I have a vague memory of a BBC(?) documentary talking about experiments carried out on prison inmates, forcing them to eat up to 10000 calories a day in exchange for shorter sentences. Apparently some of them couldn't get past a certain weight no matter how much they ate. Metabolic regulators?

I'm unsure about the rigour of the study but perhaps Robert might know more about this.

[Robert Santana]

My guess would be body fat.

I suppose if it isn't body-fat then it's muscle mass, and why would the body have a reason to get rid of muscle mass -- something that's useful for survival?

I would think that bulking/cutting works because of this fact, body gets rid of fat quickly (returning to a physiological 'norm') -- especially if you had to 'forcefully' eat to get that way, but maintains the muscle because that's important.

As for the tolerable fluctuation for an increase in weight (body-fat), I'm not sure.

I have a vague memory of a BBC(?) documentary talking about experiments carried out on prison inmates, forcing them to eat up to 10000 calories a day in exchange for shorter sentences. Apparently some of them couldn't get past a certain weight no matter how much they ate. Metabolic regulators?

I'm unsure about the rigour of the study but perhaps Robert might know more about this.

Ah yes you are referring to the Vermont Studies done by Ethan Allen Sims in the late 60s. They were investigating the effects of experimentally induced obesity on a group of prisoners in the Vermont State Prison. Essentially they took a group of prisoners, fed them in the ballpark of ~4000 calories and saw that some gained weight initially and then weight stabilized. So they had to increase the calories up to 10,000 calories to induce obesity. All meals were measured, monitored, and recorded. Several papers were published on this and I'm still trying to locate the first one so I can get a hold of the macronutrient breakdown but they said that they used "standard dietary tables," which tells me that this diet was likely moderate-to-low fat, which could explain why it required so many calories to induce weight gain. They also collected adipose tissue biopsies and this is one of the first papers to report that the fat gain was due to an increase in fat cell size and not an increase in fat cell number. Now keep in mind this is a short term study so it didn't tell us much about the long-term effects of this but it was the first to give us some insight on the biological variability in the response to overfeeding. This was later extended by Bouchard and colleagues in 1990, where they studied the effects of overfeeding on monozygotic twin pairs and reported that genetics were 9x more likely to predict the response to overfeeding than energy intake. All very cool and fascinating stuff! The short of it is if you wanna walk around super lean, then select your parents wisely!

[thras]

I recall the Vermont studies from Taubes' book. He had the following quotes from some of the doctors involved regarding the macronutrients.

According to Sims’s collaborator Edward Horton, now a professor of medicine at Harvard and director of clinical research at the Joslin Diabetes Center, the volunteers would sit staring at “plates of pork chops a mile high,” and they would refuse to eat enough of this meat to constitute the excess thousand calories a day that the Vermont investigators were asking of them. Danforth later described this regimen as the experimental equivalent of the diet prescribed by Robert Atkins in his 1973 diet book, Dr. Atkins’ Diet Revolution. “The bottom line,” Danforth said, “is that you cannot gain weight on the Atkins diet. It’s just too hard. I challenge anyone to do an overfeeding study with just meat. You can’t do it. I think it’s a physical impossibility.”

Getting their volunteers to add a thousand calories of fat to their daily diet also proved surprisingly difficult. Throughout their numerous publications, Sims and his colleagues comment on the “difficult assignment of gaining weight by increasing only the fat.” Those fattening upon both carbohydrates and fat, on the other hand, easily added two thousand calories a day to their typical diet. Indeed, subjects in some of his studies, Sims and his colleagues neglected to publish, for example, was that it seemed impossible to fatten up their subjects on high-fat, high-protein diets, in which the food to be eaten in excess was meat. According to Sims’s collaborator Edward Horton, now a professor of medicine at Harvard and director of clinical research at the Joslin Diabetes Center, the volunteers would sit staring at “plates of pork chops a mile high,” and they would refuse to eat enough of this meat to constitute the excess thousand calories a day that the Vermont investigators were asking of them. Danforth later described this regimen as the experimental equivalent of the diet prescribed by Robert Atkins in his 1973 diet book, Dr. Atkins’ Diet Revolution. “The bottom line,” Danforth said, “is that you cannot gain weight on the Atkins diet. It’s just too hard. I challenge anyone to do an overfeeding study with just meat. You can’t do it. I think it’s a physical impossibility.”

Getting their volunteers to add a thousand calories of fat to their daily diet also proved surprisingly difficult. Throughout their numerous publications, Sims and his colleagues comment on the “difficult assignment of gaining weight by increasing only the fat.” Those fattening upon both carbohydrates and fat, on the other hand, easily added two thousand calories a day to their typical diet. Indeed, subjects in some of his studies, Sims and his colleagues reported, experienced “hunger late in the day…while taking much greater caloric excesses of a mixed diet”—as much as ten thousand calories a day.

Sims and his collaborators evidently did not wonder why anyone would lose appetite—develop “marked anorexia,” as they put it—on a diet that includes eight hundred to a thousand excess fat calories a day, and yet feel “hunger late in the day” on a diet that includes six to seven thousand excess calories of fat and carbohydrates together.

The last paragraph is editorial from Taubes, who isn't always perfectly reliable. But I'd be interested to find out if it's an accurate summary or not.

[Robert Santana]

I recall the Vermont studies from Taubes' book. He had the following quotes from some of the doctors involved regarding the macronutrients.



The last paragraph is editorial from Taubes, who isn't always perfectly reliable. But I'd be interested to find out if it's an accurate summary or not.

Gary Taubes has also said that if he saw a diet that said sugar was not harmful he would not believe it. I’ve read the original publication reporting on the adipose tissue cellularity data and there was no mention of the macronutrient breakdown. I requested an interlibrary loan for the first publication to see if they mention this but I highly doubt it was a ketogenic diet because “standard dietary tables” in 1968 were not likely high protein.