Early in my career, I too believed that the key to weight loss rested in a simple mathematical equation- that of calories in must be fewer than calories out. But as I age and mature as a physician I am learning that many more complex factors are in play. The purpose of this paper is to examine what other factors need to be considered to effect healthy weight loss and optimize body fat distribution.
In an earlier post, I examined the concept of energetics and the storage of energy. I reviewed that energy is not created or destroyed, but rather transferred between sources. Energy that is stored is known as potential energy, maintaining the capacity to power an energy-requiring process, but held fallow until the correct signal or stimulus. Fat represents this kind of energy. There is little doubt that were two people were stranded on a desert island, one of high fat and high body mass, and the other rail thin, the more corpulent of the two would likely survive an extended fast longer. The fatter person has more energy stored on the body, and in the absence of a continued intake of food with the replenishment of energy stores, the processes required for life, all energy dependent, would go on for a longer period of time. Metabolic signals required for the liberation of this stored energy are activated in the fasting state; so that in this fasting state the muscles continue to contract, the heart continues to beat, and the brain continues to think.
Several metabolic processes are utilized in the body to liberate the stored energy as it is required. Without spending too much time on the multiple processes in play, I feel that it is important to review a few key players, because some of these biologic processes are the very factors that are influencing the abnormal deposition of fat in the first place. The most important hormones in respect to energy storage and utilization are cortisol and insulin. These are known as counter-regulatory hormones, meaning that they influence one another in an opposite and offsetting fashion. Other counter-regulatory hormones such as glucagon, growth hormone and adrenaline similarly oppose the function of the hormone insulin. When insulin is up, cortisol and the other counter-regulatory hormones should be down, and vice-versa.
In a nutshell, the job of insulin is to instruct cells to take in glucose (sugar) and to convert it to a storage form, the molecule glycogen. Glycogen is stored in the muscles and liver, and is the first source of energy when our blood sugar levels are low. In times of high blood sugar, say following a meal, the insulin levels should rise (while cortisol and the other counter-regulatory hormones decrease), and the energy from the meal is stored as glycogen for use at a later time.
Conversely in states of low blood sugar, by definition at least some degree of stress, the stimulus for the pancreas to secrete insulin is suppressed. Our brain, heart and kidneys don’t want our sugars stored, but liberated into the bloodstream where they can be utilized to weather a famine, fight a neighboring tribe, or escape from a tiger. Our stress hormone cortisol rises while its alter-ego insulin is rendered ineffective. Elevated cortisol instructs the muscles and liver to break down glycogen into individual glucose molecules, which can then be readily used by the end organs. Not surprisingly cortisol inhibits the activity of insulin. It doesn’t make much sense for a body to be trying to both store and utilize energy at the same time.
The secret to weight loss is to channel our energetics towards the most optimal pathways. From a functional standpoint, there are three organ systems that need to be addressed to adequately assess an individual’s energetic balance (or lack thereof). Two we have already mentioned: insulin and cortisol. It is essential that one consider the function and balance of these two hormones, as they are the backbone of energy storage and breakdown in the human body. A person in continued stress has persistent levels of the hormone cortisol, which means that they are continually trying to increase their blood sugar. Over time, this excessive and persistently elevated blood sugar is converted to fat. So has your physician considered your stress levels and cortisol levels in you assessment of your obesity? They should. It should really be the first step.
Additionally there are many individuals who have unregulated insulin function. As we put on weight, as our belt loops extend, and as it gets progressively harder to see our toes, we are slowly stressing our insulin secretion and action. At a point, insulin ceases to work at its receptor, a condition known as insulin resistance, and all the extra sugar that we consume (often in the form of excess carbohydrates) gets deposited as fat. Ironically, while we may have elevated levels of sugar in our bloodstream, our cells-are slowly starving as the insulin resistance has eliminated their ability to utilize this nutrient. Alzheimer’s disease is becoming more strongly associated with insulin resistance. Could it be that in the land of plenty- Crispy Kremes, Cinnabons, and Coca Cola- we are slowly starving our brain cells to death?
In order to fully undertake a coherent approach to obesity and weight loss, it is essential to address all the hormones and biochemistry that are involved in energy acquisition, storage and release.
The functions of insulin and cortisol begin to bring us far beyond the paradigm of simply asking the question of whether the calories in are equivalent to the calories burned. In concert with the hormones insulin and cortisol, it is essential to consider thyroid hormone as an essential regulator of the body’s energetics. Every cell in the body has receptors for this hormone, so it must be pretty important. Too much thyroid hormone and the individual is like the Energizer Bunny. Too little thyroid hormone and the patient feels and acts like a sloth. As with cortisol and insulin, there is a “sweet spot” for thyroid hormone, and effective weight management is incumbent on this essential hormone being in balance.
But what about the environment? Have we exposed ourselves to environmental exposures that promote either a state of fat or thin? Current data suggests that indeed this is the case. We should be considering the health influences of antibiotics, bacteria, hormones, and fertilizers. The medical literature is replete with papers that indicate that antibiotic exposures, hormones in our meats, pesticides and herbicides may well influence our bodies and upset our ability to correctly regulate the storage and usage of energy. Animal scientists, notably in the cattle and produce industry, have known for decades that giving an animal antibiotics increases the weight of the animal, and increase the meat’s marbling (the weaving of fat into the muscle fibers to promote flavor). So is there any reason to think that humans exposed to multiple rounds of antibiotics would be immune to similar drug- induced weight gain and muscle marbling?
There is recent published data, with growing acceptance in the medical world, that antibiotics either given to the pregnant mother, or to her infant after birth, statistically increase that child’s chance of being obese later in life. In some manner this antibiotic is disrupting a microbial balance that increases the possibility that we (and the cows) will pack on the weight later in life. It is disheartening to think that many of our children may be taking their first breaths with an established predisposition towards being obese later in life.
And what about exposure to pesticides, herbicides or other persistent organic pollutants (POP’s)? Multiple studies over the past two decades have reinforced that fact that POP exposure is strongly associated with insulin resistance (!) and obesity. I believe that an individual’s weight problems may have a strong association with ongoing exposures to environmental pollutants and toxins in their air, water and foods. Without attention to these ongoing exposures, the person struggling with increased weight and obesity may not be successful in a weight loss program that relies on calorie restriction exclusively.
Additionally we need to be considering the effects of our sex hormones, estrogen, progesterone and testosterone on our physiology and metabolism. Estrogen is a trophic hormone, which is to say that it promotes cellular growth. It causes breast growth in a preteen, enlargement of uterine fibroids, and thickening of the lining of the uterus prior to a woman’s menstrual cycle. In a nutshell it makes cells grow. Progesterone provides the balance, directing the cells towards an ordered function, growth and purpose. When in balance, the two act like a cellular “yin-yang” and good health is maintained.
But for many reasons, both men and women are finding themselves with increasing levels of the hormone estrogen. The reasons are numerous and merit a dedicated blog. Too many women are living with a disproportionate level of estrogen relative to progesterone. Too many men are living with higher levels of estrogen relative to testosterone. And what is the final outcome? On this the data is clear. There is more obesity, cardiovascular disease, and cancer risk in the estrogen dominant individuals in both sexes. It is essential to consider both sex hormones and their metabolites to comprehensively understand the factors that are contributing to an individual’s body composition.
In considering these factors, we are now able to move into a more functional, comprehensive and lasting approach towards obesity and weight loss. It is becoming clearer that weight loss is not simply an equation of eating fewer calories- although there is no doubt that calorie restriction can be an important component of a successful weight loss approach. But a thorough weight loss program must consider multiple systems to determine what factors are driving an individual’s physiology, microbiology and ultimately their metabolism.
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Dr. Scott Resnick