“Eat Less, Move More” is poor weight loss advice! If you are the least bit familiar with the laws of thermodynamics, you know that weight loss can only occur if you decrease your energy intake (more accurately, energy that is digested and absorbed) and/or increase your energy expenditure. In other words, you have to create an imbalanced energy equation. There’s just no getting around this fact, despite the numerous claims from people selling detox products that supposedly “burn off your fat” or ads for juice cleanses that “clean you up” and make you magically lose weight. Okay, so you might be asking, since it’s true that we have to create a negative energy balance to lose weight, then why is telling someone to eat less and move more inadequate weight loss advice? Well, because we have to take into account that the body is not just a passive vehicle that comes along for the ride, but rather an active organism that have systems in place for controlling body fat levels. In other words, you have to create a negative energy balance, but it should be done by working with your body.
When you tell someone who’s overweight to eat less and move more, you automatically assume three things:
- Voluntary/deliberate calorie restriction is an effective strategy for permanent weight loss (Same foods, simply less total calories).
- Exercise is great for fat loss.
- Weight loss is all about making a conscious decision to reduce energy intake and/or increase the amount of energy you burn off.
At first sight, you might think that these assumptions are legitimate. However, at closer scrutiny it becomes clear that the “eat less and move more” mantra could be doing us more harm than good. Although some studies show that a minority of people respond to exercise by losing a “significant” amount of weight, the average weight loss from isolated exercise (no dietary intervention) is modest at best. Also, the exercise-induced fat loss probably has more to do with the metabolic effects and the impact on gene expression, rather than the actual energy expenditure. In terms of diet, I don’t think there is any doubt that simply focusing on “calorie counting” (voluntary calorie restriction) is not a good approach for achieving permanent weight loss. It could play a supporting role for some people, but it definitely shouldn’t be the main emphasis. Of course, if you’re a fitness competitor who wants to get stage ready, you have to deliberately eat less food. However, that’s not what I’m talking about here. I’m talking about the regular person, often overweight or obese, who’s looking to shed the fat without going hungry all the time.
The body fights to maintain what it considers to be a balanced state
What many people aren’t aware of is that the body has systems in place that are responsible for controlling body fat levels, both on a short-term and long-term basis. As long as we understand how these systems work, we can develop a weight loss plan that allows for fat loss without hunger and fatigue.
The energy homeostasis system in our body is responsible for controlling long-term fat storage by regulating energy intake and energy expenditure through a variety of mechanisms (1,2,3,4). The fact that we have a system in our body that is responsible for maintaining energy homeostasis shouldn’t really come a s a surprise, as these types of systems are in place to regulate many other variables, such as pH and blood pressure, so that internal conditions remain stable and relatively constant.
Actually, most people are probably more familiar with these systems than they might think. Just think back at a time where you exercised more than you typically do. What happened? You got hungrier of course. The body tried to maintain what it considers to be a stable state by influencing food intake in an attempt to restore energy balance. The same thing happens if you continue eating the same diet, but simply decrease the overall volume so you eat a couple of hundred calories less every day, AKA calorie counting. You get hungry, fatigued, and more often than not, tired of the whole weight loss thing.
To illustrate this with an example that is easy to understand, let’s turn our attention from food over to the essential molecule all life on earth depends on: H2O, water. Nobody in their right minds would suggest that drinking less water for several days is an effective strategy for permanently decreasing body water levels. You will simply be very thirsty and then return to normal as soon as you start rehydrating. The energy homeostasis system is similar in many aspects. However, it’s also different in some crucial ways. Perhaps most importantly, the level of fat mass we carry can change significantly. This is something that we see everywhere in the modern world, people are getting fatter. What is really happening here is that their fat mass “set point” is increasing. In other words, the brain defends a higher level of body fat than it used to!
Fat cells talk to the brain
So, at this point you might be asking: How is possible for the body to actively play a part in these processes? To be able to understand how the energy homeostasis system works, we have to go back to 1994 and the discovery of the hormone leptin. Although researchers have known for a long time that there is a system in the body that’s responsible for regulating fat storage on a long-term basis, it wasn’t until this crucial discovery that they really started to understand how this communication between fat cells and the brain really works. The brain can be thought of as the control center in our body, and when we eat food, hurt ourselves, experience pleasure, etc., signals are sent to and from the brain.
So, what is so important about the chemical leptin? While many metabolic hormones play a role in regulating metabolism and energy balance (e.g., insulin, ghrelin), leptin is the master hormone involved in the control of fat storage (5).
Leptin is produced by fat cells, and leptin production correlates with the size of your fat stores. This is not a linear relationship, as studies have shown that even people with the same level of body fat can have different levels of systemic circulating leptin (4). However, in general, leptin production increases as you store more fat, which means that people who are overweight or obese have much higher leptin levels than people who are lean.
So, what is it really that this hormone does? Its primary function is to notify the hypothalamus about changes in body fat stores. If body fat levels decline, leptin production declines as well, leptin signaling in the brain decreases, and processes that are aimed at restoring energy balance are triggered. The primary way we can return body fat levels to normal is by eating more, so naturally, we get hungry.
If you’ve paid attention, you might be asking the following question at this point: If people who are overweight produce more leptin than people who are lean, why doesn’t the brain respond to this high level of circulating leptin by ramping up the use of stored energy? The answer to this question is quite simple. Overweight is characterized by varying degrees of leptin resistance (4,6). Basically, people who carry a lot of fat mass have decreased leptin sensitivity, meaning that leptin doesn’t produce a sufficient response at the receptors in the brain. So, the brain essentially “thinks” that the body carries a lot less fat than it does and thereby defends an elevated amount of fat mass.
This is really the only way someone can get obese, as it’s impossible to gain a significant amount of fat if the leptin system functions correctly.
So, in some ways, you are not really in control of your own food intake. You can definitely choose to not respond to the signals you get from your body, but as everyone who’s been on a calorie restricted diet for some time knows, this is an almost impossible strategy to maintain forever. Food seeking behaviour isn’t the only thing that is affected by this decreased leptin signaling; energy expenditure per unit lean mass also tends to decrease. In other words, both sides of the energy equation are affected.
And this system works both ways. What happens when researchers get a group of people together and overfeed them for several weeks? They gain weight of course; but the interesting thing doesn’t happen until the overfeeding phase is over. As soon as the subjects are allowed to eat to satiety again, they typically lose most of the gained weight (3). Basically, leptin levels are elevated, and the body detects that there has been a perturbation of body fat levels and therefore ramps up the use of stored energy.
What is really important to note is that some studies suggest that participants who are overfed for a certain period of time never return all the way back to their old weight (3). Instead, they stabilize at a body weight that is slightly higher than their previous level. In other words, their fat mass set point/range has increased. To bring this into the real world, imagine the typical holiday weight gain that some people experience. Over a long period, these increases add up.
The fat mass “set point” can change
Okay, so we don’t have to look very far to understand that this range of defended body fat can increase. A quick look at the people sitting at a McDonald’s restaurant or pizza joint is a good example of that. As we know, the obesity epidemic is spreading all over the world, and the vast majority of people now carry more body fat than their grandparents – and definitely more than their prehistoric forefathers. So, what is really going on here? Is lack of self-control the only reason people are now getting so fat. No! It certainly plays a role, but it’s far from the only factor to consider. Virtually no one chooses to be obese. So why are so many people overweight then? Well, because we’re not adapted for the modern, western lifestyle. The energy homeostasis system goes haywire when we eat a western diet, spend most of the time on the couch, take broad-spectrum antibiotics, and in general, live in a way that isn’t consistent with the way of life we are genetically adapted for.
So, I think no one is going to argue that the level of “defended” fat mass can increase. That brings us to another question: Does it only go one way, or can we lower the amount of defended body fat? I think the scientific literature shows that we definitely can. Many people manage to permanently lose weight, and dietary interventions, such as paleo diet studies, show that you can experience lasting weight loss from eating the right type of diet (7,8,9). All of this brings us back to the main point of this article. At this point you probably understand why telling someone to simply eat less and move more is not very good advice. If they simply continue eating the same diet, but decrease their energy intake (“calorie counting”), they will naturally start to lose weight, but their energy expenditure will decrease, and they will be hungry most of the time. As they decrease their intake of highly rewarding and “inflammatory” foods along with all the rest, they will most likely experience some lasting weight loss, but definitely not as much as one would expect. While some people continue with this “starvation” approach for long periods of time, it’s no doubt that it’s not a viable solution for the vast majority of folks out there.
This response to a calorie restricted diet is really just what one would expect, as leptin signaling in the brain decreases. The same goes for exercise. While exercise can positively impact weight loss though a variety of mechanisms (e.g., improved metabolic health, altered perception of food) studies show that exercise-induced weight loss is modest at best. Why? As I’ve just explained, simply expending more energy doesn’t necessarily transfer into permanent weight loss. When you burn of more energy, you’ll generally consume more energy.
Weight loss is not about counting calories and running hours on the treadmill
To really sum this up, I want to highlight the following: Although being overweight is the new normal in many countries today, this is not a natural state of the human body. Just like other animals are lean and fit when they live in their natural habitat, humans also carry low levels of body fat when we live in an environment that closely resembles the living conditions in which we are well-adapted for. Not fitness competitor leanness, but definitely within the normal BMI range. This notion is supported by studies of hunter-gatherers and isolated non-westernized populations, which show that overweight is virtually unheard of in these populations. And more importantly, they generally stay lean even when food is abundant. If we really think about, this is the expected observation, as either too much or too little body fat would jeopardise survival in an ancestral environment. Also, this clearly shows that there is something about our modern environment that’s causing the energy homeostasis system to go into a tailspin.
Okay, at this point you might be asking: What does all of this mean for me? How can I effectively lose weight? If you’ve understood everything above, you’ve probably also accepted that simply telling someone to eat less and move more isn’t very good advice. What we want is to eat less without deliberately restricting calories, and we want the body to ramp up the use of stored energy. In other words, we should live in a way so that the body wants to lose weight. This might sound like a strange thing to say, but it really isn’t. If we manage to regain control of the energy homeostasis system, decrease low-grade inflammation, and improve leptin and insulin sensitivity, then we will naturally start to lose weight. Basically, we have to become healthy. Because that’s what you quickly learn when you start reading up on body fat regulation; the things we have to do to lose weight are also the things we have to do to be healthy. That’s not to say that all lean folks are healthy (far from it) or that all overweight people are in for a quick death – but there is no doubt that the human body is healthiest when it’s relatively lean.
So, let’s round things off. How can you regain control of the energy homeostasis, improve sensitivity to key metabolic hormones, ramp up the use of stored energy, and eat less without deliberately restricting calories? I’ve discussed many possible strategies in depth before. Without going into all the details, here are the ones I consider to be most important.
- Paleo-based diet
Why? This type of dietary pattern is what we are best genetically adapted for. The types of food allowed on this diet have a low-moderate reward value, high micronutrient density, low-moderate palatability, low antinutrient concentration, low-moderate energy density, and many other beneficial characteristics. Unless you eat a lot of fruits and tubers, a paleo-type diet is low-carb compared to the typical western diet. Meat, eggs, vegetables, seafood, some types of legumes, and other simple, minimally processed foods should be the basis of your diet if you’re trying to lose weight.
- Eat more protein
Why? Protein has a potent effect on satiety and thermogenesis, and an increased protein intake can improve leptin sensitivity. The data are clear, “high-protein” diets are great for weight loss.
- Eat more traditionally fermented foods and prebiotics (especially resistant starch)
Why? Bacteria regulate our immune system, maintain intestinal barrier function, and play an important role in the regulation of fat storage and metabolism. Probiotics and prebiotics can boost fat loss.
Make sure you get enough sleep, improve your omega-3/omega-6 ratio, spend some time in the sun, and gently cook your food. Also, as previously mentioned, exercise can have a modest impact on fat loss.
Want more info on weight loss? Check out my previous articles on the subject. Also, I highly recommend the blog of Dr. Stephan Guyenet, which first opened me up to some of the ideas I discussed in today’s article.