The epidemic of obesity keeps getting worse. What's a good holobiont supposed to do?

 

The obesity epidemic keeps expanding. The above are, I believe, the most recent data available for the US. The COVID-19 lockdowns and isolation measures are reported having made things even worse. This trend is simply horrendous: what the heck is happening to humankind? (Disclaimer: I am not a nutritionist, I am just someone who is fascinated by data and trends. And, of course, we are all interested in our health! Here, I report some data I found, hoping you may find them useful. Don't take them as the last word on the subject. As always, before acting on things that affect your health, do your own search and use your judgement about what works for you.)

The obesity epidemics had a considerable boost by the lockdowns during the Covid-19 pandemic. Coupled with the opposite effect, that obesity is a risk factor for people who contract Covid, you have a remarkable disaster in the making. With several Western countries having percentages of obese people close to or higher than 50%, one wonders what's going to happen in the future. Why are the human holobionts in such a poor shape?

The story is complicated, and I don't pretend to say anything new. I just want to attract your attention to some recent studies that I think shed some light on the mechanism of human obesity (but even our fellow dog holobionts are suffering from obesity). 

First, the work by Raubenheimer and Simpson on the food preference of various animals, summarized in a recent book titled, "Eat like the Animals." (Mariner Books, 2021). Their discovery is easy to summarize: it seems that most living beings have a specific set point in their needs for the main nutrients. They seek for a specific balance among proteins, fats, and carbohydrates. In particular, they aim at a minimum intake of protein. If animals are fed an unbalanced diet, for instance, poor in protein, they will tend to eat more food until they reach the right level. Raubenheimer and Simpson call this the "protein leverage hypothesis:" 

"In a protein-poor but energy-rich food environment, humans will overeat carbs and fats to try to reach their protein target. However, when the only available diet is rich in protein, human will underconsume carbs and fats"

Since excess carbohydrates are stored in the body as fat, we can say that one of the causes of the obesity pandemic is that the human diet in Western countries is overstocked in carbohydrates. 

Here comes Robert Lustig and his book "Metabolical" (Yellow Kite 2021) where he minces no words on how this is not only true but also a profitable strategy for the food industry. They discovered long ago that if they put more and more carbohydrates (sugars) in the food they sell, then people will get fat, they will eat more, and that will increase their profits. Just like sick people are a boon for medical doctors, obese people are a boon for food producers. 

You don't believe that? Let me show you a picture I took a few days ago in an Italian supermarket:

There are four kinds of regular mayonnaise on sale, plus a fancy one with no eggs. Can you guess which is the only one that does not contain added carbohydrates? Let me tell you, it is the most expensive one among the regular ones. All the others contain sugar. Maybe it is not the same for all mayonnaise brands on the market, but I think it is significant. Food companies do add sugar everywhere, even when it is not called for by the traditional recipes. They deny that, but it is written on the list of the ingredients (I have pictures, if you don't believe me!)

Now, it may well be that there is much more to obesity than just carbohydrates, but I think that these results point at an important cause of the problem. There are data showing that what we are seeing may be a delayed effect of "peak sugar" that occurred around the year 2000. From then on, the amount of sugar consumed in the U.S. has been going slightly down. But it remains high. 

The beauty of this is that, if it is true, with obesity we don't have such a wicked problem as others, say, global warming. We know that to avoid global warming, we should stop burning hydrocarbons, but it is also true that we can't just stop: billions of people would die. But we could stop, or at least strongly reduce, the extra carbohydrates added to processed food, and we could do it today. Nobody would die, but the problem would be eased and many people would be healthier! But this is the way things are in the world: no problem can ever be solved when there is somebody making money if it remains unsolved. 

To make you happier, let me show you some data that tell us that a little excess weight (a little!) is not necessarily bad for your organism. Here are some data from Malcolm Kendrick's wonderful book "The Clot Thickens" (Columbus 2021). 

BMI stands for "Body Mass Index" and the overall lowest risk of death is for a BMI of 25-30 that's normally classified as "overweight" (if you want to know, I am at BMI=27). Being underweight is a larger risk than being obese! But obesity has many other problems, not least in terms of self-esteem. 

In the end, remember that you are a holobiont and that for hundreds of millions of years your holobiont ancestors never ate anything that was processed in an industrial plant. You are a fine-tuned machine that includes trillions of friendly viruses and bacteria living in your guts. They want a balanced diet of fats, protein, fiber, and not too much in terms of carbohydrates (but you need them, too!). Try to make them happy, and you'll be happier, too!

A Diet for the Human Holobiont.

 

A picture taken at an open-air market near Florence in 2015. As you see, overall, people are not fat in Italy. But that doesn't mean we don't have our share of obesity problems. 

The human holobiont is a wonderful machine that can do many things in many different ways. It has a "dual fuel" system that allows it to subsist on two main kinds of foods: one his carbohydrates, the other is fat. You probably know something about how switching to the fat-based metabolism can improve your health and reduce your weight. That's called the ketogenic, or "keto" diet. 

I won't go into the details. I just wanted to tell you that I am experimenting now with a relatively new version of the ketogenic diet, called sometimes the "pseudo-fasting" or "Fast-Mimicking Diet," developed by prof. Valter Longo presently at the USC university but, incidentally, born in Italy. 

The story of this and other similar diets is long, but the basic concept is always the same: you tend to mimic the way the human holobiont machine would work in its natural environment. There, it wouldn't normally have a 100% daily supply of high-energy content carbohydrates, from Corn Pops to ice cream. And, clearly, this kind of diet is not good for us for many reasons. Not only it makes us obese, but it also generates diseases such as diabetes, high blood pressure, high blood cholesterol, all that. It is called the "Metabolic Syndrome"

Recognizing the problem, led to several proposals to solve it: diets, mainly. One is the "paleo diet," others involve intermittent fasting. In all cases, you try to reduce the amount of carbohydrates you eat. The idea is to exploit the capability of your body to switch to use fat as an energy source. It is a different concept than that of the "standard" diets, which often consist of reducing calories without worrying too much about what kind.

At the basis of the ketogenic diets, there is the idea that you mimic a condition that your ancestors would normally encounter in their lives: that of running out of food. We store energy in the form of fat just as a precaution against that event. When we don't have enough carbohydrates, we can switch to fat and that makes us leaner and fitter. Our body "understands" that there is a problem and it moves to remedy it. Under the ketogenic regime, you are on the prowl. You are searching for food. 

So, how is the pseudo-fasting working? I can tell you about my personal experience. I am not obese, just moderately overweight. The main reason I am trying this diet is to reduce my blood pressure without using pills -- and all the typical problems you have as you age (I am 68): gastro-esophageal reflux syndrome, sleep apnea, pre-diabetes, if you are over 50 you know about that.  

The version of diet that I am following involves a reduced food intake: 40 grams of nuts and about 400 grams of vegetables per day -- plus a little olive oil (a must for Italians!). As I am writing this post, I am on the 4rth day of a 5-day cycle. It seems to work: I can see that I am in the ketogenic mode using "keto sticks." I've lost about two kgs, so far. Not much, but it is something, and I am still halfway through the cycle. And my blood pressure is going down, nothing dramatic, but a little, yes. 

What I think is interesting is how the pseudo-fasting diet is a relatively easy diet to follow. In the past, I had tried the alternate fasting diet, you fast one day and you eat normally the other. It is fine, but I found it a little harsh. At least for me, pseudo-fasting was much easier: a little hungry the second day, but no problems the other days. The beauty of the idea is that you don't separate yourself from the rest of your family at mealtimes. You eat with them, although, of course, you eat very little and food of low nutritional value. 

I also think it is important that this diet is not made to punish you by making you hungry. We tend to think that our ancestors were primitive brutes and would go hungry all the time. No, not at all. As Chuck Pezeshki explains, humans are social animals and tend to share food. There must have been times harder than others, but hunger must have been rare, just as over-abundance. Hunger and obesity are maladies of what we call "civilization." So, I think the pseudo-fasting diet does mimic something that our ancestors would experience: periods of scarcity where they had to cope by being smart and efficient and make the best use of their (our) dual-fuel metabolic system.

Then, of course, I am experiencing the same sensations that I had with the more conventional fasting. All sensations that are part of the evolutionary tools you have inherited from your ancestors: you feel more tired, but also more alert. You tend to conserve energy, but you are ready to go into running mode if you see a potential steak in your hunting range. Or, more likely, edible berries not so far away. A peculiar sensation is the different range of vision. Somehow, I tend to detect things at a larger distance, noting details that I don't normally note. I don't know if this is common, but it makes sense: if you are on the prowl, then you have to be alert for any possible food source, even a distant one. 

Then, of course, when you are on a diet, you tend to dream of eating good things! But I figure that it is normal. I woke up this morning while dreaming of caviar and champagne. Yes, like James Bond and Vesper Lynd in "Casino Royale." A diet that gives you this kind of dreams must have something good in it!

So, how does that relate to the concept of holobionts? Well, it is because you shouldn't forget that what keeps you alive is a large number of little creatures inside your cells: the mitochondria. They are the source of energy for everything we do, but, remarkably, they don't share your genetic code. Their DNA is just theirs, you inherit them from your mother and not from your father. For some reason, when the female ovum is fecundated, the mitochondria carried by the male spermatozoa are destroyed and disappear forever. So, mitochondria are creatures living inside the human organism. They are a perfect example of symbiosis: they couldn't live without you and you couldn't live without them! That's how holobionts function. 

And we keep going. Who knows? One day we could find a way to stop the obesity epidemic that's making so many people sick and unhappy in the world. Onward, fellow holobionts!

To go more in-depth, do read this wonderful post by Chuck Pezeshki. And thanks to Dr. Alberto Santini for having placed me on the pseudo-fasting track!