Losing weight without eating less calories

In the previous blogposting, I argued in favor of a whole food diet. Such a diet allows us to lose weight without eating less calories. The argument was based on invoking the extreme robustness of living organisms. Evolution should not have made us prone to becoming overweight when we eat as much as we please! Animals in the wild don’t get obese, so why are we prone to getting overweight?

Could it be that most animals in the wild are just at the limit of being in calorie deficit? This is the traditional explanation, but it’s not all that plausible given the robustness of living organisms in their natural environment. If our ancestors in the wild were teetering at the edge of starvation, we wouldn’t be here. Nevertheless, this is a popular view and it misinforms us about the way we should tackle the obesity problem.

Animals in the wild are generally not teetering at the edge of starvation, they are thriving. Their bodies simply adjust the metabolic rate to balance their energy budget. They maintain a healthy setpoint for their fat reserves.

The reason why we’re prone to becoming overweight is because the food we eat is not natural. Our food contains an unnaturally high amount of refined fats and sugars. The key to long term sustainable weight loss is then to eat whole foods. But why would this make a difference given that most of us do get the recommended amounts of vitamins and minerals?

As I pointed out here, getting all our calories from whole foods will yield far more fiber and magnesium, about double the RDA. So, boosting the fiber content of the diet by eating more whole foods is an obvious way to improve the diet. In this blogposting I’ll consider why eating more fiber will lead to weight loss. I’ll conclude with my recommendations for getting started with losing weight according to the methods I advocate.

Eating more fiber lowers the bodyweight

As I explained here in the previous blogpost, the amount of fat reserves we have is regulated with the aim of keeping our energy reserves stable. This is implemented by hormones excreted by fat cells. If fat cells become emptier, the metabolic rate will be slowed down. Fat cells will then start to accumulate more fat as a result. Traditional dieting methods don’t work well, as they fight this mechanism.

The smart way of losing weight is therefore to lower the setpoint for body fat. Once the setpoint is lowered to the target body weight, you can eat pretty much as much as you like, and you’ll not gain much weight. If you do gain a bit of weight, e.g. after Christmas, you’ll be back to your ideal weight within a matter of days, without having to diet.

So, is it then plausible that getting more fiber in the diet will lower the body fat setpoint? Why would fiber have such an effect? It’s perhaps better to ask why not getting the naturally normal amount of fiber will have the opposite effect.

Why does eating more fiber lower the body weigh?

A diet low in fiber in the natural context means that we’re not eating a normal amount of plant-based foods. We would instead be surviving on animal food products. Such a situation could be typical for a harsh winter, or a drought and it comes with a high risk of famine. Clearly, this would have led to a body design via natural selection that would increase the body fat setpoint when eating a low fiber diet, if such a body design were physiologically possible.

So, is it possible for the body to increase the body fat setpoint if we change the amount of fiber in the diet? If we change the amount of fiber in the diet, does the body get a signal that it can act on to modulate the metabolic rate?

How fiber is able to change the body fat setpoint

What is known is that the fiber we eat is food for our intestinal microbes. The more fiber we eat the more intestinal microbes we have and we’ll also have a more diverse set of such microbes. These microbes produce chemical compounds, some of which such as butyrate play a role in many biochemical processes in the body.

The net effect of these chemical compounds is still the subject of scientific investigations. But the mere existence of all these chemical compounds that are capable of influencing metabolism, makes it possible for fiber to modulate the metabolic rate. We can then assume that as a result of evolution we would have ended up with a body fat setpoint that depends on fiber intake.

Other ways to influence bodyweight

Besides eating more fiber, we can think of other ways to get to a lower body fat setpoint. Let’s first look at sleep. It is known that sleep deprivation tends to lead to weight gain, biochemical pathways by which this happens in case of accute sleep loss have recently been uncovered. But it’s helpful to try to understand why evolution would have led to this outcome.

Why sleeping less causes weight gain

Why would animals in nature sleep less? Typically this will happen if they need more time to find food. This is then a signal that points to an increased risk of food shortages. One should thus expect that sleep deprivation will cause to the setpoint for body fat to increase.


The effect of exercise on bodyweight is usually assessed via the amount of energy burned in exercise sessions. One then reaches the conclusion that exercise isn’t all that effective compared to an energy restrictive diet. It takes a massive amount of exercise to burn off the energy consumed in one big meal. However, as I’ve pointed out in this and the previous blogpostings, what matters more for the bodyweight on the long term is the setpoint the body chooses to maintain.

Why would the setpoint for body fat change due to exercising regularly? When living in nature, being physically fit means that you are able to walk larger distances to find your food should that be necessary. This thus lowers the chance of experiencing food shortages. But it’s no good if far away you can find a lot of food, if it takes more energy to get there than is present in the food. But the lower the body weight the less energy it costs to walk long distances.

The fitter you are, the lower your body fat setpoint

So, the fitter we are the more advantageous it is to have a lower bodyweight to prevent food shortages. We should thus expect that evolution has led to a body design that lowers our setpoint of body fat if we become fitter. Exercise is thus a good way to maintain a healthy bodyweight. Even short bouts of exercise that don’t burn a significant amount of calories can be helpful. What matters is then that physical fitness is maintained, rather than any individual exercise session.

Intensive exercise sessions that do burn lots of calories are, however, going to be more effective. If you burn 1000 Kcal by running for an hour then that will give you a lot of room to eat a lot more. It also enhances the appetite you need to eat healthy foods.

Eat at least 80 grams of fiber a day

As I pointed out here, eating 2500 grams of whole foods typically yields 70 grams of fiber. But we don’t eat only energy rich foods, we also need to eat vegetables and fruits and these foods also contain lots of fiber. A good diet based on whole foods should then yield at least 80 grams of fiber.

The problem is then that eating this way requires gradually getting used to the large amount of fiber. Also the volume of the food will be much larger than people are used to eating. Indigenous populations who eat this way who come into contact with Western civilization very quickly start to eat the Western-style low fiber high fat diet and then start to experience high levels of obesity and type-2 diabetes.

Once accustomed to the Western diet there is no easy way back to the original diet. Just like our muscles, the gut also degenerates when you don’t use it. Not eating enough fiber means that you lose the gut flora and it takes lots of time and effort to regain it. It this makes sense to think of this issue as a “gut fitness” issue. I’ll discuss this in the next blogposting. I’ll also talk about other health aspects of a whole food diet besides obesity.

Getting started on losing weight without eating less calories

If you want to lose weight by eating more fiber, I can recommend starting slowly by getting used to a low fat, high carb diet. This diet program (paid link) is an excellent way to start. You’ll then gradually eat more fiber while you’ll start to lose weight. It’s also helpful to learn to prepare tasty healthy meals. I can recommend this book (paid link) on vegan recipes. Even though I’m not advocating veganism, it’s still healthy to eat vegan menus, and one can always add some meat to a vegan plant-based meal.

A more rigorous way to get started is to follow the Forks over Knives diet (paid link) . This is again a vegan diet but a low fat one,it will you bring close to what I’m arguing for here. My arguments presented in this blog are not always in agreement with these vegan programs or the arguments presented in the high carb weight loss program, but what matters is that the conclusion on what type of a diet is the best to eat, is quite similar.

Another possibility is to lose weight under my personal guidance. You then need to fill in this form.

How to lose weight without eating less calories

We all know that we can lose weight by eating less calories. When the body uses more energy than it is taking in, this result in fat loss. A deficit of 3500 Kcal of energy will result in one pound of weight loss. However, many people who do successfully lose weight end up struggling to prevent weight gain. They need to stick to a low calorie diet and have to tolerate being hungry all the time.

But many people won’t put up with this struggle, they may moderate their calorie intake a bit and as a result they end up not losing enough weight. Having to tolerate discomfort in order to be at a healthy weight doesn’t sound like a natural state for the human body. Surely there must be a more natural way to achieve a healthy bodyweight? In this blogpost I’ll dig deeper into this issue to see where the real problem lies. This will then suggest far better ways to tackle the problem.

This rather long-winded blogpost is organized as follows. In the next section I’ll consider the energy balance aspect of weight loss. This will lead to the insight that fat tissue influences metabolism. I’ll then present another argument based on evolution that corroborates this.

To get to better ways to lose weight, we must find factors that influence the way the fat tissue affects metabolism. The arguments that can lead us to the answer will again be based on evolution having led to a robust body design. I’ll then first explain why we can trust these sorts of argument.

I then conclude this blogpost by identifying the main properties of a diet and lifestyle that should lead to a healthy bodyweight without having to stick to an energy restrictive diet. Impatient readers may want to jump ahead to that section straightaway.

The fundamentals of weigh gain and weight loss

So, we know that eating less calories will cause weight loss, it’s then tempting to think that eating too many calories is the cause of being overweight. But that’s false! What is true is that eating more calories than you burn will cause weight gain. But once you are at a certain weight and you are not gaining or losing weight, you are burning as much energy as you are absorbing from your diet.

Example: Jane wants to lose weigh

Suppose that Jane is overweight, she weighs 220 pounds while 175 pounds is her ideal weight. She is now eating 2500 Kcal a day and not gaining or losing any weight. A 1700 Kcal diet will bring her at her target weight in about 7 months time. But she wants to avoid the burden of being in calorie deficit and having to fight off your body’s tendency to move back to her old weight. So, we need to ask why Jane can’t be at 175 pounds while eating 2500 Kcal.

Jane’s body mass of 220 pounds can be considered to be the sum of 45 pounds of excess fat she wants to get rid of and the 175 pounds she wants to keep. Now fat has a metabolic activity of 2 Kcal per pound per day. So, Jane’s body minus the 45 pounds worth of fat tissue is actually using 2410 Kcal a day. Part of this energy use comes from the burden of having to carry 45 pounds of weight.

Now, this burden of carrying that excess body fat can be replaced by exercise once Jane is at her target weight. And that exercise is what she is already doing now by carrying her excess body fat, so this won’t require gaining physical fitness. So, it should in principle be possible for Jane to weigh 175 pounds and still eat about 2400 Kcal by exercising more. Nevertheless, the fact that people tend to regain their weight when they stop dieting, suggests otherwise. What’s the problem?

Why does overweight Jane have a faster metabolic rate than slim Jane?

What’s the difference between Jane weighing 220 pounds with 45 pounds excess fat and Jane having lost 45 pounds of weight, carrying a rucksack weighing 45 pounds all day long as exercise? Why can she eat 2500 Kcal with no weight gain in the former case while in the latter case she’ll gain weight until she’s back at her old weight?

The difference can’t be explained by the 90 Kcal energy use of the 45 pounds of fat tissue. Muscle tissue uses 6 Kcal per pound per day at rest but much more during exercise. After exercise muscle tissue will also use more energy which is needed for recuperation. While this is known to play a role when people have lost a significant amount of muscle mass, people experience problems maintaining their new weight regardless of muscle mass loss.

Fat tissue influences metabolism

There is then only one possible explanation left. Fat tissue must influence the metabolism, more body fat causes the body to rev up the metabolism. How can this work? It is known that fat cells produce hormones. If fat cells become full, they the produce the hormone leptin that will suppress hunger. This hormone was only discovered in 1994. Since then other hormones produced by fat cells have been discovered:

Recently discovered hormones produced by fat cells

Some of these hormones influence metabolism, they have been discovered only in the last few years. So, it’s quite plausible that there are many more such hormones to be discovered. Now, we arrived at the conclusion that fat tissue is involved in regulating metabolism by invoking the fact that people tend to regain their old weight after weight loss if they stop dieting. Let’s consider a more powerful argument based on evolution that can guide us to find the right diet for weight loss.

Bodyweight regulation

Human beings are warm blooded mammals. Our bodies constantly burn energy at quite a fast rate. Clearly mammals could only have evolved under circumstances where food is not scarce. However, there are always fluctuations in the amount of food an animal is able to find. This requires the animal to have sufficient energy reserves.

It’s then also necessary to regulate the metabolic rate to make sure the energy reserves won’t get depleted or won’t grow out of bounds. Without such a regulatory system, an animal could starve to death if it had to expend just a little amount of energy more to find its food, or become extremely obese due to eating just a little more and becoming just a a little less active.

Suppose for example that we would expend 150 Kcal a day more and eat 150 Kcal a day less. Then that’s a deficit of 300 Kcal per day, causing us to lose 1 pound of body fat in about 12 days. If this were to go on indefinitely, we would eventually starve to death.

Fat tissue modulates metabolism to keep energy reserves stable

It’s just not plausible that warm blooded organisms could have evolved without a feedback mechanism that modulates the metabolic rate depending on how much energy reserves the animal has. So, if fat cells are full, the metabolic rate should be higher than when they are empty. This way the energy balance is stabilized on the long term and large fluctuations in the bodyweight are prevented.

But this then seems to imply that the amount of fat reserves is fixed at some level. However, evolution will have led to a mechanism that regulates the metabolic rate, so that animals can survive large shortfalls of food for long enough. This then translates into some setpoint for the amount of body fat, which in turn is determined by other factors that determine how much body fat is necessary to survive for some time without food.

We can then speculate about these other factors based on the idea that evolution should have led to a well designed, robust body. But since we’re then going to run way ahead of the science, let’s first consider how reliable we can expect such arguments to be.

Robustness of living organisms

When we go about our usual business, we tend not to consider that we are extremely complex self-maintaining machines. This is not how we perceive our own body. Our self-image when taken literally is overly simplistic. In our minds our bodies are simple machines that we use in our daily lives, like cars or refrigerators. To get an idea of the real complexity of life, let’s watch this short excerpt of a video by Jack Szostak on the origin of life:

Excerpt from Jack Szostak’s video on the origin of life where he discusses the complexity of modern life.

So, each cell in our body harbors an enormously complex biochemical machinery. One cannot compare a single cell with a machine like a car. A single cell is more similar to the set of all machines in all factories in a small country. At that level there are regulatory mechanisms like managers of companies, a political system, there exists an economy that feeds back on how the factories are operated.

This extremely complex system has been shaped by evolution to optimize the physical properties of the body as a whole needed for survival. We should thus expect living organism in their natural environment to be extremely robust systems.

Algorithmic view of life

The biochemical machinery in our cells implements algorithms that make our body function in a very robust way. We’re able to deal with many problems that can arise within a broad range of natural conditions. A perturbation away from an ideal condition will trigger a reaction that will counteract that perturbation. Each cell in your body is constantly at work maintaining the right conditions. The collective effect of all the actions by all cells in an organ make that organ function in the right way, and all the organs in the body make the entire body function as a robust system.

The enormous complexity of the biochemical machinery in each cell originally evolved to let microbes survive in a challenging environment. When multicellular life evolved, part of this complexity could be used for the benefit of the organism as a whole. Evolution has optimized the available cellular machinery into useful tools for the organism it is part of. This has then led to organisms that are very adaptable to challenging environments.

The four zones of life

A perturbation away from an ideal state will lead to lots of biochemical processes that will undo the effects of the perturbation. The stronger the perturbation, the more urgent it becomes to counteract the perturbation. However, any organism will have physical limits to what it is able to deal with. This means that up to some limit, it will be able to respond to stronger perturbations with with faster and more elaborate restorative processes. We can schematically illustrate this using the following diagram:

Diagram illustrating the perturbations away from the ideal state
The green zone represents states that are close to ideal, the orange zone represents less than ideal states, the red zone represents states that are not survivable on the long term and require emergency actions to move back to the orange region, the black zone represents states where the organism is dead or irreversibly damaged and dying as a result.

In the green zone, the organism is close to its ideal state, but there can still be significant perturbations here that are dealt with vigorously. In the orange zone the internal state of the organism has been compromised to such a degree that this affects its ability to deal with additional perturbations. The organism is then in an unhealthy state. It may then resort to stronger restorative actions that in the green zone would not be taken. It may e.g. react with an inflammation to an infection when that same infection in the healthy green zone would not have led to an inflammation.

In the red zone, the health of the organism is so bad that it’s going to die on a short time scale unless it is able to move to the orange zone. A movement into the red zone will trigger very strong biochemical responses to steer the organism back to safety.

For example, if the organism is deprived of oxygen, it will gasp for air, it will do everything it can to move as fast as possible to the orange zone. If it is unable to do that, its biochemical machinery will get damaged beyond its repair capability. It will then end up in the black zone which corresponds to the dying or dead state.

Maintaining optimal health and fitness in our modern society

The problems many people have with weigh loss seems to contradict the robustness of the human body. While we have seen that we can explain many of the problems people experience with controlling their weight from the point of view of robustness, the setpoint for the amount of body fat seems to be too high. The explanation for this can only be that our lifestyles in our modern society is too far removed from the natural lifestyles our bodies have evolved to adapt to.

What are then the relevant differences between the modern diet and the diet our bodies have evolved to eat? As I’ve pointed out in this comment in the British Medical Journal, a very important difference between the modern diet and a diet based on whole foods, is the amount of fiber and certain minerals like magnesium.

High ratio of fiber and magnesium to calories in whole foods

It turns out that the ratio between fiber and calories is remarkably similar for many of the natural energy rich foods. Even when comparing foods rich in fats like nuts to foods rich in carbs like potatoes yields a similar order of magnitude.

Getting 2500 Kcal should then yield at least 70 grams of fiber, which is way more than the RDA of just 40 grams, which in turn is way more than the 20 grams most people get. By not getting enough fiber, we deprive our intestinal microbes of enough food, so we end up with a microbiome that’s not as robust as it should be.

For the mineral magnesium, which is known to play an important role in metabolism , the same is true. Getting 2500 Kcal from natural foods should yield at least 0.7 grams, which is almost double the RDA, while most people get a lot less than the RDA.

Eliminate refined fats and sugars from the diet

The reason why most people end up eating way less than than the natural amounts of fiber and magnesium, is because a significant fraction of the calories in modern our diets comes from refined fats and sugars. This causes us to eat far less of the natural sources of energy that contain fiber and magnesium.

The key to getting to a healthy body weight is thus to get the calories from the natural sources. But because fat and sugar are extremely compact sources of calories, this requires getting used to eating vastly larger volumes of food. A change to a natural diet has to be done gradually, not just to get the body chance to get used to the large volume of food, but also to get used to the far higher fiber content of the diet.

One can then ask why eating more fiber and magnesium will cause the setpoint of the amount of body fat to be set to a lower value? I’ll answer this question in the next blogpost. I’ll also discuss the effect of exercise and proper sleep on the bodyweight.

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