The conventional wisdom in the study of how our bodies regulate feeding has previously suggested a simplistic view that there are two parallel systems in our brains that interact to influence our food intake. New research suggests something quite different. This view of the interaction between these two conceptualized systems "is not likely very accurate, because there is a high level of communication between these two systems" The complexity of this interaction may explain in part why it's so hard for us to control our eating.
This was the opening message that over 100 professional health care providers and members of the general public were delivered at the Institute of Natural Resources Food Addiction, Obesity and Diabetes program recently in Scottsdale Arizona.
One health care professional attending was Registered Dietitian Nutritionist Bonnie Roill, RDN, CPT, CHC, MBA, owner of Scottsdale based Aspire 2 Wellness and B3 Nutrition. Bonnie, who's also a Hormone Cure Coach© and the organizer of The Boomer Women's Weight Loss Club meet-up group. Bonnie shared some of the details on why it's so hard for us to give up the foods we love to eat.
It all starts within our brain.
The Homeostatic System is the first system and it is vital to our survival. Our brain is the command center for regulating our appetite which includes a complex dance between hormones, neurotransmitters, neuropeptides, and macronutrients such as carbohydrates, proteins and fats. Our bodies are designed to maintain a balance between our needs for energy derived from foods and our intake of the food. Without this drive for "homeostasis" we wouldn't have survived all these eons. However, in the past 30 years something has interrupted this homeostasis resulting in the obesity epidemic.
The second system at work is called the hedonic or pleasure-reward system. Our brains are hardwired to respond and seek rewards that are essential for survival through the hedonic system. This system drives the homeostatic system to encourage us to eat and to store sufficient calories to protect us from the potential of future starvation or famine, based on the palatability of food or fluid. This palatability varies ... it is lower after consumption and higher when deprived. Palatability of food and fluid can however, be learned. The pleasure-reward system is activated when we eat food that is pleasurable thus making us more likely to seek out that food again. The more pleasurable, the more we seek it. This can create a hedonic hunger that is independent of homeostatic needs.
Eating experiences are individualized by sensory modalities such as taste (super-taste buds); mouth feel (how food feels or explodes in our mouth); smell (think freshly baked hot bread!); and gut factors (receptors detect sweetness as early in the GI tract as the esophagus) and go all the way down into the stomach and even the pancreas!
The two systems, homeostasis and hedonic, are in constant communication and in the perfect world would be a check and balance to ensure we consume enough calories for our survival and reproduction of the human race. The obesity epidemic has been blamed on the concept that we live in an obesogenic environment and our two systems can't handle the 24/7 availability of food.
Taking this a step further, some claim that we can develop an addiction to food based on the concept that the intake of pleasurable tasting foods uses the same region of the brain that is activated in response to drug by abusers. In fact, Dr. Nora Volkow, Director of the National Institute of Drug Abuse states that "it's more difficult for people to control their eating habits than narcotics." Neuro-researchers have shown that highly palatable foods and drugs of abuse race along the same pathway sending out the message to consume more!
Food that is palatable prompts us ... drives us ... to seek out and eat more, even when we're not physically hungry. So what makes food palatable? What makes foods so palatable that they can make us overeat to the point of feeling "Thanksgiving stuffed" at any time of the year?
Palatability is influenced by:
1. Processed foods. No surprise here. The mixture of foods refined by industrial processes, such as sugar, flour, salt and certain fats are typically mixed with flavor enhancers and chemical additives. These food-like products are ingested in a form that triggers an excessive release of neurotransmitters, similar to recreational drugs, which can promote compulsive intake and loss of control.
2. High sugar / high glycemic load carbohydrates. Sugar, a type of a carbohydrate known as a disaccharide, is classified as addictive based on animal models. When sugar is found in fruits and vegetables it's found in smaller concentrations and coexists with other natural substances like fiber, vitamins and trace minerals that have numerous beneficial benefits.
Any substances addictive potential is determined by its potency and a rapid rate of absorption. The concept of glycemic load refers to how a carbohydrate containing food raises the blood glucose level. Highly refined carbohydrates have a rapid absorption rate causing a spike in the blood glucose level, followed by a surge of neurotransmitters (chemical messengers crossing over the brain into other organs of the body. The body responds to this increase in blood glucose by a sudden drop resulting in increased hunger.
Human studies have shown that a high glycemic load shakes triggered the hedonic system resulting in increased hunger resulting in overeating in spite of adequate caloric intake. Take home message: avoiding highly processed/refined/high glycemic load carbohydrates can help people avoid overeating.
3. High fat. Many people crave fatty foods, like melted cheese, full fat ice cream, and cream of broccoli soup. Eating foods high in fat have not shown to trigger the same circuitry followed by drug abusers but animal studies have shown that another mechanism may be involved in cravings for high fat foods. This may be why you can't just eat 12 almonds!
4. Salt. Some researchers believe that salty food might be an addictive substance that stimulates the reward-pleasure system. Research to date has been on animal models yet shows once again, that salty foods encourages more salt binging. This may be why "you can't just eat one" of your favorite chips. The food industry uses salt as the answer to making cheap, unpalatable food edible at a very low cost.
5. The combination of sugar and fat. Animal models show that rats will work hardest for a food that combines sugar and fat. The combination of these two food components promoted weight gain in rats vs. a diet only high in sugar or a diet only high in fat. Fast food scientist have taken this combination to create "food" with super addictive palatability. Add to this clever and constant marketing; enticing food-eating restaurant environments, and a stressful day, enough for the primitive human brain to be easily hijacked to overeat.
6. High fructose corn syrup (HFCS). The controversy over HFCS still continues yet some facts cannot be overlooked. Fructose follows a different pathway than glucose. Breaking down fructose results in an increase in hunger and creates a strong desire for food. Interesting side note; the special properties of fructose resemble that of alcohol. Just like alcohol, when fructose is taken in large quantities, it can result in neurobiological changes (the brain begins to change the way it responds and even looks!)
7. Food availability, it's visual appeal, incentives (i.e. Value Meal); social situations revolving around eating, and advertising and marketing are other factors that influence the potential for food addictive-like behaviors.
In spite of these factors we can find our way home to homeostasis. It starts with a desire to change, realizing that eating habits don't change overnight and seeking support to help with our obesogenic environment. Mindfulness practices and discovering other health promoting avenues to get enjoyment out of our lives is key to re-training our brains.
This information is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical/nutritional/fitness advice. Information presented is subject to change as additional discoveries are made or additional research is published.