"Know the body is merely a garment. Go seek the wearer, not the cloak." - Rumi
If you are of a certain age, you may remember when, in 1988, Oprah Winfrey pulled a little red wagon of fat onto the stage of The Oprah Winfrey Show as a dramatic representation of the 67 pounds she lost while following a liquid diet. That episode was one of the most watched in the long history of her show. Millions tuned in to see a size 10 Oprah pulling that wagon full of animal fat, tapping into our culture’s obsession with weight and the collective disdain associated with fatness. But the fat in Oprah’s little red wagon was not equivalent to the complex, dynamic fat tissue in our body. Human body fat, rather than being an inert blob, is an incredible feat of evolution that is essential to our survival. Indeed, humans would not have survived to this point in history, developed complex behavior, nor created sophisticated cultural systems if it weren’t for the amazing capacities of body fat.
Adipose tissue—what we refer to as fat--is not an inert mass of blubber, but rather a critical metabolic organ that serves many important functions, most of which are related to energy storage and production. One of the most important functions of adipose tissue is regulating metabolism. Our body gets energy from two main sources, glucose and fat. Glucose is stored as glycogen in our muscles and liver. It is a quick source of energy that is tapped into when we need immediate fuel. As glycogen sources are depleted, the body burns fat which yields significantly more calories once it is released from storage. Stores of glycogen are limited, but adipose tissue is uniquely designed to store this fat in the form of lipids, a droplet of energy elegantly encased and suspended within a thin cell membrane. These lipids store enough energy to allow us to survive for weeks without eating. In our current environment of sedentary lifestyles and food surplus, storing fat may be undesirable, but long ago, when our ancestors hunted and foraged for food, they frequently went for weeks without adequate calories. Adipose tissue evolved as a survival tactic that enabled us to function for long periods without food, freeing us from the tyranny of having to eat continuously. Due to the readily available warehouse of energy in adipose tissue, our brains got larger, we migrated further, our societies became more complex, and our capacities expanded. Essentially, our fat is what helped us to evolve.
Adipose tissue serves other important functions related to metabolism and our endocrine system, including the release of hormones that regulate feelings of satiety, and those correlated with insulin sensitivity. But there are many other factors and functions this organ provides that we are still learning about, some beneficial and others harmful to our overall metabolic health. Endocrinologists have known for decades that adipose tissue, fat metabolism, and energy regulation are highly complex mechanisms. Most of the research done today continues to defy the pervasive cultural myth that fat is “bad” and weight is a simple equation of calories deficits and energy expenditures.
Research related to adipose tissue’s role in metabolism and health offers plenty of clues but very few answers. It seems there is considerable variability in everyone’s adipose tissue; it is highly adaptable and sensitive to a person’s particular genetics, environmental cues, and the functioning of other body systems. That explains why your annoying cousin can give up ice cream for a month and lose 20 pounds while you count every calorie only to gain weight. In addition to individual differences, there is growing evidence that adipose tissue plays an important role in inflammation. As recently as 2019, researchers identified a protein on the surface of fat cells that regulates metabolic and inflammatory responses. It seems that when the body is under stress, this protein responds by initiating an inflammatory response which shuts down our ability to burn fat. Keep in mind that adipose is our energy warehouse. Inflammation is the body’s response to threat, so decreasing metabolism when we are stressed is an adaptive response, much like lifting the drawbridge, locking the castle door, and hoarding supplies in anticipation of a battle. This reaction may be held over from our ancestors, who faced frequent periods of food scarcity. However, our ancestors rarely lived much past their 40’s. It could be that this receptor becomes problematic over time, as we live much longer and are exposed to more stressors. Could this be one reason why weight control becomes problematic as we approach middle age? Once again, research gives us clues but no definitive answers.
Contrary to what we’d like to believe, our understanding of weight loss, weight gain, and obesity is murky, at best. We do know that people’s metabolisms vary—a lot. Some of this variance may be related to the numerous species of microbes that live in our gut—it is host to about 100 trillion bacteria. It seems these bacteria act as gatekeepers between what is eaten and what is absorbed in the small intestine. A rich diversity of these bacteria is essential for reducing inflammation and regulating metabolism. There is compelling evidence that the types of bacteria in the gut can alter our capacity to extract calories from food. That explains why two people can eat the same 500 calorie slice of pizza and one will not see any change in weight whereas the other will gain 2 pounds.
Scientists are getting a clearer picture of the role diet plays in maintaining a healthy level of diversity in the gut. Do certain types of foods promote bacterial growth? What is the role of probiotics in growing beneficial bacteria? Although there is still a great deal to learn about how the body regulates these bacterial communities, scientists are fairly certain that the immune system plays an important role. It could be that what we are exposed to at an early age—medications, infections, processed foods—can disrupt our immune system and change the way it identifies and interacts with certain microbes. How this happens and what factors trigger such a response are still mysteries to be solved.
Although the myth of calories in, calories out is overly simplistic, there is still an element of truth in that equation. Scientific evidence and personal experience confirms that what we eat does impact our weight. But are all calories created equal? Does the body burn 200 calories of M&M’s the same way as 200 calories of grapes? The short answer is that there is a difference but, once again, we don’t know why. Studies have found that processed foods, even when they have the same caloric value as natural, unprocessed foods seem to result in greater weight gain. In one interesting study, researchers had subjects live for several weeks in a controlled setting in which they were fed an equal number of calories and had the same level of physical activity. One group was fed a diet consisting only of unprocessed fruits, vegetables, whole grains, and lean meats. The other group ate meals that came exclusively from processed sources, essentially a fast food diet. By the end of the study, those who ate the processed foods gained more weight than their counterparts, even though each group ate roughly the same number of calories. Other studies have shown that processed foods are digested differently than whole foods and may stimulate inflammation. It may be helpful to shift our attention to what we are eating rather than simply counting calories.
If all this uncertainty about weight is confusing, scientists promise that what we know about the relationship between critters in our guts, the inner workings of adipose tissue, and the impact of processed foods will undoubtedly become more complicated in the future. One thing we do know for certain is that losing and maintaining a healthy weight is incredibly difficult for many people. The best advice from the experts is to eat a wide diversity of fruits, vegetables, and whole grains to help maintain a diverse community of gut microbes, keep your immune system strong, and reduce inflammation. Although this advice is not heavy on detail, it is more helpful than the tired "eat less, move more" advice.
For now, perhaps this research can help diminish our culture’s moralizing and judging associated with body weight. At the very least, it can help us appreciate the complexity of human physiology and highlight the importance of our relationships with nature, culture, and environment. Weight gain and loss is not analogous to an energy piggy bank. Yet our culture continues to promote the idea that diets work and anyone who struggles with weight is somehow flawed. If that were true, why do so many people—at least 80% of dieters—fail to lose weight? And of those who do lose weight on low calorie diets, why do over 90% fail to keep it off?
Perhaps we can start by examining our relationship with our body. How do we live inside of our skin? Do we appreciate its complexity and the amazing ways it adapts to our world? Or do we take it for granted, tune it out, and listen only when it calls out for help? There is a growing string of evidence that connects weight gain to inflammation. There are hints that inflammation is the body’s way of sounding the alarm, sending up a flare to signal that our metabolism is out of whack. By tuning in to listen, we might sense these imbalances and make changes way before we reach a state of distress.
Interestingly, mindful eating practices are gaining attention as promising ways to change our relationship with food. Approaches that shift our thinking away from moralistic thinking—certain foods are “good” or “healthy” while others are “bad” or “fattening”—have shown to be highly effective in stimulating gradual and modest weight loss. Importantly, the weight that is lost is maintained for much longer than other weight management approaches. Mindful eating does seem to improve our relationship with food, as people who use mindful eating techniques tend to binge less often, select more unprocessed foods, eat more slowly, and report a much higher level of satisfaction in the entire eating experience. They are less stressed about food and report more positive feelings related to body image.
Take a moment to examine your relationship with your body. Are you happy in your own skin? Are you grateful for the amazing things your body does for you? Or do you hold rigid expectations of what it should do, only to be disappointed when it comes up short? When I find myself in a loop of endless self-criticism, I stop and ask whether I would be so critical of my family, a friend, or even a client. I am reminded that my body is doing the best job it can, in the present moment, given the resources it has available. Let’s shift away from faulty and simplistic thinking to explore all the gifts we receive from our amazing, adaptable, complex human body, the only home we have on earth.
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