As we approach 2015, many people are thinking about their resolutions for the year, which often include weight loss. Weight loss and long-term maintenance can be a challenging endeavor—and it pays to understand why.
Barriers to Weight Loss
Research has taught us that there are two primary barriers to weight loss and maintenance:
- Adherence to an effective weight control program. It doesn’t work if you don’t stick with it.
- The brain’s “starvation response” opposes weight loss.
Remarkably, one of these two key barriers to weight loss typically flies under the radar. Let’s take a closer look.
Since the pioneering experiments of Bailey, Bremer, and Smith in the 1920s, researchers have known that a part of the brain called the hypothalamus has a profound influence on body fatness (1). Simply by inactivating the basal hypothalamus of dogs and rats, these researchers were able to produce ravenous overeating, morbid obesity, and metabolic dysfunction. As it turns out, this works in humans as well: naturally occurring tumors that damage this same brain region lead to a phenomenon called hypothalamic obesity—one of the most intractable forms of human obesity (2).
The reason hypothalamic obesity is so intractable is that it flips a switch in the very system that the brain uses to regulate body fatness—activating a starvation response designed to pack on the pounds. This is an exaggerated version of the same starvation response that occurs when a person loses fat.
In hypothalamic obesity, the starvation response is activated because brain damage disrupts a fat-regulating system that works a bit like your home thermostat. A thermostat measures ambient temperature using a thermometer, compares it to a set value programmed by the user, and uses heat or air conditioning to correct deviations in either direction. This is called a negative feedback system, and it’s used by engineers and nature alike to stabilize important variables. Similarly, the hypothalamus measures body fatness using a hormone called leptin that’s produced by fat tissue in proportion to its volume (3). The hypothalamus then compares the amount of fat tissue to its own internal “body fat setpoint”, and uses a variety of responses to correct deviations in either direction (but it seems particularly concerned with preventing deviations in the downward direction). The hypothalamus tries to prevent changes in total fat volume.
Hypothalamic obesity disrupts the ability of the hypothalamus to detect the leptin signal, making the brain think there is no leptin and therefore no body fat—a dire situation! The brain pulls out all the stops to try to gain fat. It acts as if it’s starving, doing its best to bring in more calories and hold on to any calories (fat) the body already has.
But one of the more interesting things about this starvation response is that a less extreme version of it can be triggered even if a person has an intact hypothalamus, and isn’t actually starving. All it takes is for the brain to perceive that a person is starving, even if, in reality, he has plenty of body fat to spare. This is exactly what happens when a person loses weight, due to the decline in leptin that occurs.
When a person loses weight and leptin levels decline, the hypothalamus senses that fat stores are shrinking. In response, the hypothalamus activates a suite of responses designed to regain the lost fat (3). The hypothalamus sits at the helm of a number of controls that it uses to accomplish this. It turns on hunger centers in the brainstem, and activates food reward centers in the forebrain. You become hungrier and your interest in high-calorie foods increases. Researchers can demonstrate this by showing images of pizza and cake to weight-reduced people, and watching parts of their brain light up more than in people who haven’t lost weight (4). The hypothalamus sits on top of the pituitary gland, which controls the activity of the thyroid gland via thyroid-stimulating hormone. When the hypothalamus thinks a person is starving, it dampens her thyroid hormone signaling, lowering her metabolic rate and making her feel cold (5). It also dampens the activity of the sympathetic nervous system, which further reduces her body’s calorie usage (5). Weight loss stalls. These responses to weight loss are largely reversed by injecting leptin, showing that the reduced leptin signal is what the hypothalamus is responding to (4, 5).
This means that many overweight people can have a very hard time losing excess body fat, because the body fights it as though it were starving. It also means that maintaining weight loss is equally challenging. However, no one wants to lose weight temporarily. This presents a serious problem for the would-be dieter, and something worth considering in a weight loss program.
The archetypal weight loss approach, calorie counting and restriction, works in theory but it requires the dieter to exert constant willpower to fight his or her own body’s tendency to want to retain and regain body fat. In other words, this approach pits the conscious willful mind against the hypothalamus. The “I want to look good in a bathing suit next summer” mind has to contend with the “I’m hungry and that food looks really good right now” mind—and research shows that the hungry mind usually wins in the end.
A New Approach to Weight Loss
Fellow researcher Dan Pardi and I set out to design a new approach to weight loss—one in which the goals of the conscious willful mind and the hypothalamus are aligned, leading to easier, more sustainable weight loss without calorie counting. This is a principle that a variety of diets have inadvertently tapped into—including low-carb and Paleo diets, which don’t require calorie counting to produce weight loss (to be clear, calorie intake does decrease, it just happens as a result of the food rather than through a conscious effort to cut calories). We decided to take a step back and design a system that focuses on this principle and optimizes it. The result is the Ideal Weight Program.
The Ideal Weight Program is a web-based system that addresses both primary barriers to weight loss. First, it focuses you on key diet and lifestyle strategies that help to minimize the brain’s starvation response, facilitating fat loss and maintenance. Second, it helps you stay engaged with key weight control strategies on a daily basis, enhancing long-term adherence to the diet and lifestyle factors that really work. It does this by using an innovative behavior modification system developed by Dan Pardi, which he recently explained in his presentation at the Stanford Medicine X conference.
Our goal is to help you get results and maintain them. The Ideal Weight Program isn’t based on Exotic Secrets from the Borneo rainforest—or any other secrets for that matter. It’s based on established scientific principles, some of which you may already be familiar with. Our approach is simple: keep people consistently focused on the most efficient strategies, day after day.
Because so many people decide to start a weight loss program at the beginning of a new year, we’d like to provide extra help to those who choose to pursue that goal. Robb has graciously agreed to help us host an audio Q & A session that will be made available to all members of the Ideal Weight Program before the end of January 2015. Any Ideal Weight Program member can submit a question about the Program or related topics via this link. All Ideal Weight Program members will receive an e-mail when the Q & A session is live.
Wishing you health and happiness in 2015,
Stephan Guyenet, Ph.D.
Dan Pardi, M.S.
Click this banner above to find out more, and be sure to listen to the podcast below where Robb talks with Stephan and Dan about weight regulation, weight loss, and the Ideal Weight Program.