3.4
Homeostasis, Hedonic Eating, Set Point, and Allostasis
Homeostasis
Homeostasis is the tendency of a system to try and maintain internal stability (balance) in a coordinated response to any situation or stimulus that would disturb normal functioning. Stability is maintained by the constant adjustment of biochemical and physiological pathways throughout our body and most of these are directly related to the functioning of mitochondria in our cells. Probably the best example of homeostasis is thermogenic regulation of body temperature. If we get too hot, we sweat. Some adjustments occur with little or no action or our part; others prompt US to take action. If we’re severely dehydrated, we’ll experience an overwhelming desire for something to drink. When our metabolism is in long-term balance, normal energy homeostasis is maintained [22, 23].
There are two mechanisms involved in the regulation of food intake. The short-term signals (hunger & satiety) that occur with the onset of eating and the long-term regulation food that’s regulated by our stores of body fat [22, 23]. Adipose (fat) tissues communicate with the central nervous system to maintain whole-body energy homeostasis [23]. Recently it’s been discovered that there’s a vast network of central nervous system nerves that connect adipose tissues (white, brown, and beige fat) to the brain [24]. When normal brain functioning is impaired by inflammation and immune system dysfunction, then regulatory mechanisms such as conversion of adipose tissue and thermogenic energy management mechanisms are disturbed [24]. This dysregulation leads to increased deposits (storage) of unhealthy white fat tissue [24].
Hedonic Hunger
Hunger is biochemically induced only in the event of serious energy depletion. That means for most of us, mealtimes and food choices are influenced by social, cultural, and lifestyle factors. Hedonic hunger describes the desire and drive to eat for pleasure in the absence of an energy deficit [22, 23]. Often this type of eating is associated with an emotional state that drives the desire to mood-alter and change how we feel. Hedonic eating may be in response to frustration, anger, sadness, loneliness, boredom, resentments, feeling overwhelmed, and more. In the brain, the (feel good) mu-opioid receptors (MOR) and cannabinoid receptors play a significant role with regards to hedonic eating and our attraction to appetizing foods [25]. It’s thought that dysregulation of the MOR and cannabinoid systems significantly contributes to the development of binge eating disorder [25, 26]. We’ll learn more about the addictive nature of certain foods in chapter four however, hedonic forecasting (hedonistic anticipation) may be a subconscious motivator behind dysregulated consumption. Without giving it much thought, we know that reaching for certain foods almost always boosts our moods.
Fatty foods have a high hedonic rating, because they are tasty and the most concentrated source of energy. Fat does contain nutrients essential to growth and development [21]. But in general we consume too much of it. Until WE retrain our brain reward system, fatty foods are more attractive than foods higher in proteins and complex carbohydrates. The biological mechanisms that once ensured our survival during periods of famine, haven’t evolved to keep pace with the emergence of our current fat infused obesogenic (fast-food) environment. In fact, the human adaptation of storing energy in fat cells has become a dangerous and deadly liability [22, 23, 26].
Overconsumption of hedonic Nutrient Deficient (ND) foods:
Causes disruption of energy homeostasis that negatively affects brain reward circuitry.
Results in compulsive food intake.
Contributes to overeating behaviors.
When we deplete certain reserves in our brain or stores of body fat, we know we’re unconsciously driven to replenish those reserves. When we recognize why we crave or reach for certain foods to restore ourselves, WE can take charge!
Recognition: What percentage of your eating (or drinking) behavior is directed to intentionally satisfy homeostatic needs?
Recognition: Can you identify some of your hedonistic food cravings?
Set Point Theory
The set point theory of weight management suggests that our body weight is regulated around an ideal level and that hormonal and neural signals (to eat) are activated when our fat stores fall below a certain level [27]. The good news is that we can change our set point! There are several models that explore weight gain. The first and most common explanation is the energy balance model (EBM). This model, based on physics, holds that weight gain is generally caused by an imbalance of energy intake and energy expenditure [27]. When we consume more food than our body needs, we gain weight.
Calories (a measure of energy) come from several sources, predominantly, fat, carbohydrates, and protein. To maintain a neutral weight, the EBM model suggests that we need to moderate our caloric intake and nutrition to match our anticipated expenditure of energy. That if we want to lose weight, we probably have to reduce our caloric intake and increase physical activity when able. A problem with this model is that it considers all calories to be alike, in particular, carbohydrates.
A different approach is the carbohydrate – insulin model (CIM) [26]. To explore energy imbalance, this model takes into account the quality of food, glycemic values of foods, and glycemic loading (GL) to explore the relationship between types of food and weight management. The glycemic index is a measure of how foods with carbohydrates affect blood sugar levels. GL is a combination of the total carbohydrates and the GI factor. Foods high in sugar, processed grains, and potato products are high GL foods. These foods are digested rather rapidly which cause a significant drop in blood sugar after just a few hours, stimulating a strong desire to eat again. Conversely, berries, nuts, most fresh fruit and non-starch vegetables are moderate to low on the GI scale, absorbed by the body more slowly and result in us feeling satisfied longer. CIM posits that the hormonal response to specific foods high in GL increases fat storage, resulting in a positive energy imbalance. (In this case positive isn’t good) [27].
Allostasis
It’s plausible that for most of us, hedonic eating has emerged as the dominant drive with respect to eating behavior and food preferences (when, what and why) [28]. Our preferences have shifted toward energy-dense ultra-processed nutritionally deficient foods (UPND) that have been engineered to promote overconsumption in the absence of hunger [29]. Allostasis is the path to change. Allostasis suggests that we can shift learned set points either positively or negatively and achieve stability through implementing sustainable changes. The person whose operating range has shifted to active food addiction suffers from allostatic dysregulation. Put simply, overcompensation and overconsumption prompted by cravings, has shifted their functional range from one of satisfaction and normalcy, toward an unhealthy state.
3 Principles of Allostasis
The most efficient regulation is anticipatory (question cravings…plan nutrition ahead)
The “defended” level of a set point can and should change to adapt to a new operating range. (Body adjusts to lower BMI with a decrease in “fat” seeking)
Optimal regulation is achieved by taking command in the brain (US – PFC)
Allostasis and the 4 Principles of BreakThrough!
Recognition – new information and awareness inform and motivate our efforts to make healthy choices.
Resistance – takes advantage of brain plasticity (its ability to change). Self-coaching and disputing skills help us rewire new neural circuits and override Betty. We actively challenge self-defeating, impulsive, or emotionally driven “old” thoughts and behaviors.
Resilience – develops as the result of consistent and purposeful resistance. This describes a new state of brain regulation that defaults to choices that support wellness and longevity.
Recovery encompasses both an improved capacity for optimal regulation as well as a new operating range.
Resistance: You can shift your set point! What will you do differently today?
Course Presentation Slides
Quizzes
