Happy Monday everyone! How was your weekend? Mine was good and pretty relaxing, since my Thursday night got a little crazy – more to come on that later, maybe. Today I am actually going to be sharing a post that I had to write for a biological psychology class of mine. Much more of an introduction isn’t really necessary so here it is! Hope you guys like it
Think about any weight loss advice you have ever heard. Eat less, move more. Calories in, calories out, right? A study done by Crum, Corbin, Brownell and Salovey (Crum, Corbin, Brownell & Salovey, 2011) shows it may not be that simple. There could be another key player in this seemingly simple equation, and that player is your mindset.
But first, let me explain a little background information on hunger and the body’s response to it. Ghrelin, a hunger hormone, is a major component of this study. When the stomach is empty, it releases Ghrelin. Ghrelin travels through the blood stream into the brain. In the brain, ghrelin communicates with the hypothalamus and the brain’s pleasure areas (Kyle, 2014). Ghrelin is responsible for initiating the feeling of hunger and, therefore, eating. Ghrelin is indicative of a lack of energy (Crum et al., 2011). Ghrelin also slows metabolism. This goes back to evolutionary times when people did not know when their next meal would be coming since they constantly migrated and food could be scarce. They needed to conserve what energy they did have until they found food again.
Leptin is another hunger hormone that does the opposite of Ghrelin. Once food enters the stomach and the body has energy, leptin is released and travels to the brain to inhibit eating. Leptin will also speed up metabolism to start breaking down all the calories the body has just consumed (Kyle, 2014).
In the study, Mind over milkshakes: Mindsets, not just nutrients, determine ghrelin response, the researchers discover that our belief of what we have consumed factors into our biological response to that food. In the study by Crum et al., they had forty-six participants. The researchers had all participants drink a 380-calorie milkshake and told them it was an “indulgent” 620-calorie milkshake.
Figure 1: The nutrition label the participants saw for the believed indulgent 620-calorie milkshake. Source: Crum et al., (2011).
The researchers measured the level of Ghrelin in the blood at three different points throughout – once before the study began to get a baseline measure, again after reading the fake nutrition label, and one last time after participants consumed the milkshake. A week later, they had participants drink the same 380-calorie milkshake, but this time told them it was a “sensible” 140-calorie milkshake.
Figure 2: The nutrition label the participants saw for what they believed to be the sensible 140-calorie milkshake. Source: Crum et al., (2011).
Again, researchers measured the levels of ghrelin at the same three points. Crum et al. found that there were higher levels of ghrelin in the participants after consuming what they believed to be the “indulgent” 620-calorie milkshake than after consuming what they believed to be the “sensible” 140-calorie milkshake. Below is a video from National Public Radio (2014) that reiterates the explanation of the study.
In essence, we have some control over our metabolism and feelings of hunger. Perhaps it is not just as simple as the age-old equation of calories in must equal calories out. Rather, this is a perfect example of a mind-body connection. Our bodies are a lot more complex than we think. We can basically trick our bodies into thinking we have eaten more or less than what we actually have eaten.
Not only does thinking we ate a lower calorie or lower fat food make us feel less satiated after consumption, but it also slows down the metabolism. A slower metabolism means a slower burning of the just consumed calories. I don’t think anyone wants a slower metabolism.
Think about all those foods that are labeled low-fat, non-fat, low-calorie, light or diet. Those labels may actually be more detrimental to our health than helpful (Geersten, 2014). According to the previously discussed study, Mind over milkshakes: Mindsets, not just nutrients, determine ghrelin response, if we think we are consuming fewer calories, we are likely to be left with a feeling of unsatiety, and end up eating more of that food. When eating, we need to understand that not only do our stomachs have to be left feeling full, but our minds do as well.
In the study, the participants never saw the real nutrition facts before consuming. This is not necessarily applicable to the real world. We do not have someone putting fake nutrition facts on all of our foods. Outside of this study, are we still able to trick ourselves? If we look at a nutrition label and see the true nutrition facts, is it possible for us to think a food is more filling than what it actually is? Will we still see a lesser amount of ghrelin in the blood post-consumption than we would if we believed in the actual nutrition facts. Vice versa, is it possible for us to trick ourselves into thinking a food is less filling than what it actually is, and see a higher amount of ghrelin in the blood post-consumption than we would if we believed the actual nutrition label.
This study is an excellent example of the mind-body connection. Our bodies are programmed to ensure our survival with hormones that excrete to initiate the feelings of hunger and feelings of satiation. Stomach is empty? Okay, ghrelin is released, and appetite kicks in, we eat, filling up our stomachs. These hormones – grehlin and leptin – also work to adjust our metabolism, to help us store fat for survival. Yet, in spite of the innate mechanics of our bodies, our brain can convince us that we need to eat more than what is really necessary. The brain is a powerful and influential control center – and we can use it to manage our intake of food if we remain conscious of the connection between mind and body. With will power, we should be able to adjust our mind to work in tandem with the body’s hormonal gears.
Crum, A. J., Corbin, W. R., Brownell, K. D., & Salovey, P. (2011). Mind over milkshakes: Mindsets, not just nutrients, determine ghrelin response. Health Psychology, 30(4), 424-429. doi:10.1037/a0023467
Geersten, L. (2014, May 12). “Mind over Milkshakes” – Think yourself full! Retrieved from http://empoweredsustenance.com/think-your-way-full/
Kyle, Ted. (2014). Ghrelin: The “Go” hormone. Retrieved from http://www.obesityaction.org/educational-resources/resource-articles-2/general-articles/ghrelin-the-go-hormone
NPR. (2014, April 14). A milkshake experiment. [Video file]. Retrieved from https://www.youtube.com/watch?v=pIfhxt0JCok#t=25