Sunday, October 24, 2021

You can eat a lot during the Holiday Season and gain no body fat, as long as you also eat little

The evolutionary pressures placed by periods of famine shaped the physiology of most animals, including humans, toward a design that favors asymmetric food consumption. That is, most animals are “designed” to alternate between eating little and then a lot.

Often when people hear this argument they point out the obvious. There is no evidence that our ancestors were constantly starving. This is correct, but what these folks seem to forget is that evolution responds to events that alter reproductive success rates (), even if those events are rare.

If an event causes a significant amount of death but occurs only once every year, a population will still evolve traits in response to the event. Food scarcity is one such type of event.

Since evolution is blind to complexity, adaptations to food scarcity can take all shapes and forms, including counterintuitive ones. Complicating this picture is the fact that food does not only provide us with fuel, but also with the sources of important structural components, signaling elements (e.g., hormones), and process catalysts (e.g., enzymes).

In other words, we may have traits that are health-promoting under conditions of food scarcity, but those traits are only likely to benefit our health as long as food scarcity is relatively short-term. Not eating anything for 40 days would be lethal for most people.

By "eating little" I don’t mean necessarily fasting. Given the amounts of mucus and dead cells (from normal cell turnover) passing through the digestive tract, it is very likely that we’ll be always digesting something. So eating very little within a period of 10 hours sends the body a message that is similar to the message sent by eating nothing within the same period of 10 hours.

Most of the empirical research that I've reviewed suggests that eating very little within a period of, say, 10-20 hours and then eating to satisfaction in one single meal will elicit the following responses. Protein phosphorylation underlies many of them.

- Your body will hold on to its most important nutrient reserves when you eat little, using selective autophagy to generate energy (, ). This may have powerful health-promoting properties, including the effect of triggering anti-cancer mechanisms.

- Food will taste fantastic when you feast, to such an extent that this effect will be much stronger than that associated with any spice ().

- Nutrients will be allocated more effectively when you feast, leading to a lower net gain of body fat ().

- The caloric value of food will be decreased, with a 14 percent decrease being commonly found in the literature ().

- The feast will prevent your body from down-regulating your metabolism via subclinical hypothyroidism (), which often happens when the period in which one eats little extends beyond a certain threshold (e.g., more than one week).

- Your mood will be very cheerful when you feast, potentially improving social relationships. That is, if you don’t become too grouchy during the period in which you eat little.

I recall once participating in a meeting that went from early morning to late afternoon. We had the option of taking a lunch break, or working through lunch and ending the meeting earlier. Not only was I the only person to even consider the second option, some people thought that the idea of skipping lunch was outrageous, with a few implying that they would have headaches and other problems.

When I said that I had had nothing for breakfast, a few thought that I was pushing my luck. One of my colleagues warned me that I might be damaging my health irreparably by doing those things. Well, maybe they were right on both grounds, who knows?

It is my belief that the vast majority of humans will do quite fine if they eat little or nothing for a period of 20 hours. The problem is that they need to be convinced first that they have nothing to worry about. Otherwise they may end up with a headache or worse, entirely due to psychological mechanisms ().

There is no need to eat beyond satiety when you feast. I’d recommend that you just eat to satiety, and don’t force yourself to eat more than that. If you avoid industrialized foods when you feast, that will be even better, because satiety will be achieved faster. One of the main characteristics of industrialized foods is that they promote unnatural overeating; congrats food engineers on a job well done!

If you are relatively lean, satiety will normally be achieved with less food than if you are not. Hunger intensity and duration tends to be generally associated with body weight. Except for dedicated bodybuilders and a few other athletes, body weight gain is much more strongly influenced by body fat gain than by muscle gain.


Anonymous said...

Hi Ned,

How has your weight held up over the years of the improved dietary and lifestyle changes?

I am 5ft 10 inches 165# and will drop weight if I eat to satiety two meals let alone one. I need about 3000 calories or I lose weight.

When I was IF I got near 150# and people were worried about me. At that point I ate as much as physically possible for two meals and was still dropping.


Ned Kock said...

My weight has been stable for years.

Let us assume that your maintenance caloric intake is 3,000 kcal/d, and that you spend a whole day without eating anything. If all the calories come from fat, you’d lose about 333 g of weight in that day. That is a bit less than 1 lb.

Now, spending 3,000 kcal/d with your stats; I’d say you are very physically active – correct?

HaplessKiller said...

Hi, have you seen Nassim Nicholas Taleb's comments on this topic? Here is a post from his facebook. What do you think of his suggestion to randomize fasting with power law frequency?
"Lessons from 3 episodes of fasting for ~44 hours.
Recall that the Antifragile likes stochasticity and variability (by Jensens's Inequality), up to a point. So in order to allow myself to comment on the literature on Intermittent Fasting and modeling it mathematically (skin-in-the-game), I just completed today 3 fasts of ~44 hours each over 11 days (only water & black coffee) and I can report the following.
1) BARBELL - It is easier to fast completely than diet. The idea of life is to never have the brakes on when eating. But also when fasting, it is not a good idea to be tempted: you put yourself in a state of arousal for food by eating "a little bit". Hunger comes and then goes away after a cup of coffee.
I would say the combination fast+good meals with no inhibition was absolutely thrilling.
2) MAIN INSIGHT- The body is effectively an information machine, food brings metabolic noise, and it thanks you for resting.Fasting is like silence after being in NYC's Time Square. It is like not watching the news. Then food becomes more differentiated...
3) HEALTH BENEFITS - I may be subjected to placebo effect, so I can't comment except via negativa: nothing wrong.
4) WEIGHT LOSS - beyond expectation, and in the right places, but that was not the point. I lifted weights during fasts to signal the system to avoid cannibalizing muscles, but maybe it's a bad idea.
A- Caloric restriction may not extend life expectancy, and it is a completely different mechanism from IF (Intermittent Fasting). We are made for unsteadiness, not to be "thin". Data shows that thin people don't outlive slightly overweight ones. We have hints that diabetes seems more the result of hunger-deprivation than being overweight since diabetics can be cured after a long fast and weight loss and do not immediately relapse upon gaining back the weight. It takes ~ 3-6 months which hints to us the frequency of famine. So it looks like we are made for a cycle of deprivation, on which next:
B- Matching the randomness in nature, it is silly to want to inject routine into fasting. We need (say) 1 day a week, 2 days a month, ..., and 1 week a year, with powerlaw frequency. My next fast will be 4 days, etc.
C- The video below has some focus on metrics like IGF shIGH, but it includes the best researchers. Valter Longo is the most rigorous and understands proteins are bad for us, see Orthodox fasts. Proteins harm our kidneys, but we recover if we ingest them-then rest, like acute-stressor-with-recovery vs. a constant-dull one.
D- Discovered that there is a huge Russian literature on fasting as it was clinical practice (21 days), discounted because it doesn't follow modern protocols, but should be replicated. "

Ned Kock said...

The power law idea was discussed by Art Devany a while ago. I think randomization makes sense, not only for IF but also for exercise.

HaplessKiller said...

He just posted a relative frequency table for fasting lengths.

JimR said...

Glad to see another interesting and intelligent post, Ned, thanks.

In the usual academic fashion, I will skip all the things I agree with and pick at an item I question. Clearly you are right about how selection works. The main selection events, even if time-rare, are critical.

You say "we may have traits that are health-promoting under conditions of food scarcity" and that seems obviously right. The main such "health: (actually life) promoting trait, I would suggest, is calorie storage/sparing. Fat is a wonderful storage method to bridge scarcity.

In the modern western world of affluence, lots of fat is not important and perhaps unhealthy in the elderly (the 'perhaps' is because we should be talking about the evolution of exercising people with lots of fat and those may not be unhealthy people). In the situation we probably evolved in fat is life saving. On such basis I would find it strange that in times of scarcity when we might find a rare feast (a big kill? a patch of edible roots?) that we would throw away 14% of the "excess" calories. Storing those might be the life-death difference.

Ned Kock said...

Hi Jim. One way the 14% can be explained is that protein and carbs are “better utilized” after a period of low caloric intake, not being used for energy, which would lead to a lower caloric value for them. This is supported by the percentage being inversely correlated with the fat content of the meal; more fat, less caloric loss.

When protein and carbs are in circulation and not quickly absorbed into various structures and glycogen reserves, they are (i.e., the protein and carbs) prioritized for use as energy over fat. This leads to a higher caloric value for the meal. But when tissues become more sensitive to protein and carbs (aminos and sugars), due to need, they are removed from circulation faster.

Personal training said...
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JimR said...

Ned, thanks for the explanation. You are saying that, with intermittent fasting, there is an increased tendency to use amino acids (and some calories captured from carbs) for building muscle and other tissue rather than fat storage? That I could understand. I would wonder if in the long-term (order of a year, say) equilibrium with equal exercise and identical total diet there is a major difference in body fat percent based on the dynamics of food intake but it is conceivable.

Like you though, I am struck by how much paleo thought is focused on macronutrient distribution and how little on dynamics (particularly on the dynamics of "exercise").

I have been doing a modified IF for 10+ years because I find the psychology of calorie control is easiest that way.

Happy Holidays

Ned Kock said...

Certainly the idea that 14% is simply “wasted” to “keep us thin” goes counter evolutionary thinking. On the other hand, we seem to be adapted to endure regular turnover of stored protein and sugar, not only fat. For example, autophagy, which is a health-promoting process, doesn’t happen if no loss of structural protein occurs. Replenishing stores of protein and sugar seems to always consume more energy than replenishing stores of fat.

David Isaak said...

Hi, Ned...

I've been expecting for some time that you would hold forth on the USC research on fasting and immune system regeneration (Longo, et al, and their fasting/chemo work). They seem to think 72 hours is the sweet spot, though that seems to be with respect to immune resetting--not general apoptosis and clean-up.

But the whole topic of fasting is becoming more interesting...

Ned Kock said...

Do you have a link for the article David? Btw, there has been recent research linking ghrelin and the immune system, e.g.:

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Pierre said...

Ned thank you for your efforts. Here is that link to the study discussed in comments.

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Ned Kock said...

Spam comments above deleted.

Ned Kock said...

This post is a revised version of a previous post. The original comments are preserved here. More comments welcome, but no spam please!

Anonymous said...

Ned, you often seem to favor a 20ish hour fast, one meal a day feast? I too find this a very satisfying way to live alot of the time.

You mention randomness, how often do you do such fasts, do you ever spend time living on one meal a day 'routinely' or do you think that would not be beneficial?

Ned Kock said...

Hi Anon. I see fasting as a form of liberation (see post linked below), as opposed to a carefully planned activity. If it is convenient, I’ll fast. Also, during the Holidays, it “adds” extra flavor to the foods and keeps body fat gain in check.

As it turns out, I can gain weight, which is mostly body fat, extremely easily (see below). It is during the end of year Holidays that many people gain body fat that stays with them until the next Holiday Season, when they gain more … and so on.

Anonymous said...

Thanks Ned, I agree with your feelings of liberation, and the extra satisfaction of a meal after a fast!

What I'm getting at is that I too no longer look at meal timing plans as some magic scheme that must be followed, and so would eat(or not) when convenient, but it turns out, without really trying or planning, that convenience is popping more and more often.

So my question would be, do you think their would be much downsides if it happened you ended up fasting quite often?

Is there a too often?

Ned Kock said...

This post is a revised version of a previous post. The original comments are preserved here. More comments welcome, but no spam please!