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.

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

This post has been revised and re-published. The original comments are preserved below. Typically this is done with posts that attract many visits at the time they are published, and whose topics become particularly relevant or need to be re-addressed at a later date.

Boring is another word for satiating

Satiety is a common topic of discussion on this blog. In the last few posts it came up several times in the comments’ sections. Also, in my interview with Jimmy Moore, we did talk a bit about satiety. I told him what has been my perception and that of many people I know, which is that the least satiating foods tend to be foods engineered by humans.

(Source: Wellnessuncovered.com)

There is another component to satiety, which applies to natural foods, or foods that are not man-made. That other component is the nutrition value of those foods, and whether they meet our nutrition needs at a given point in time. If our body needs certain essential amino acids for tissue repair, subconscious mechanisms will make us crave those foods from which those amino acids can be extracted. In this context, eating is generally a good idea.

The problem is that we have not evolved mechanisms to differentiate “true” from “fake” nutrient starvation; one example of the latter would be fat starvation due to transient hyperinsulinemia induced by refined carbohydrate-rich foods.

Foods engineered by humans tend to lead to overeating because humans are good engineers. In modern society, business drives everything. Food business is predicated on consumption, so engineered foods are designed so that one person will want to consume many units of a food item – typically something that will come in a box or a plastic bag. There is no conspiracy involved; the underlying reason is profit maximization.

When we look at nature, we typically see the opposite. Prey animals do not want to be eaten; often they fight back. Eggs have to be stolen. Plants do not want their various parts, such as leaves and roots, to be eaten. Much less their seeds; so they have developed various defense mechanisms, including toxins. Fruits are exceptions to this rule; they are the only natural foods that are designed to be eaten by animals.

Plants want animals to eat their fruits so that they can disperse the plants’ seeds. So they must be somewhat alluring to animals. Sugar plays a role here, but it certainly is not the only factor. The chemical composition of fruits is quite complex, and they usually contain a number of health-promoting substances, such as vitamins. For example, most fruits contain vitamin C, which happens to be a powerful antioxidant, and also has the ability to reversibly bind to proteins at the sites where sugar-induced glycation would occur.

Many modern fruits have been bred to be resistant to diseases, more palatable, and larger (usually due to more water retention). But, fundamentally, fruits are products of evolution. So how come we don’t see fruits that are pure sugar? Watermelons, for example, are often referred to as “bags of sugar”, but they are only 6 percent sugar. Ice cream is 25 percent sugar.

Two things must be kept in mind regarding fruits and their evolution. One is that dead animals do not eat fruit, and thus cannot disperse seeds. Sick animals would probably not be good candidates for fruit dispersion either. So the co-evolution of fruits and animals must have led fruits to incorporate many health-promoting attributes. The other is that seed dispersion success is correlated with the number of different animals that consume fruits from a plant. In other words, plants do not want all of their fruits to be eaten by one single animal, which must have led fruits to incorporate satiety-promoting attributes.

Often combining foods, adding spices, and so on, is perceived as making those foods exciting. That is so even with natural foods. If you read the descriptions of the foods consumed by healthy isolated populations in Weston Price’s Nutrition and Physical Degeneration, you will probably find them a bit boring. A few very nutritious food items, consumed day in and day out, frequently without heavy preparation. Exciting foods, requiring elaborate and time-consuming preparation, were consumed in special occasions. They were not eaten regularly.

The members of those healthy isolated populations were generally thin and yet lacked no important nutrients in their diet. They were generally free from degenerative diseases. Their teeth were normally strong and healthy.

Just before writing this post, I took six whole sardines out of the freezer to thaw. I will prepare them as discussed on this post, and eat them with a side of steamed vegetables for lunch. (I tend to eat fruits only on the days I exercise; typically 3 days out of 7.) This lunch will be very nutrient-dense. I will be very hungry before lunch, since I’ll have been fasting for 16 hours, and after I’ll not be hungry until dinner. Frankly, eating the sardines will not be very exciting, since I’ve been doing this for years.

Boring is another word for satiating.