Have you ever felt really full after eating a piece of cake? Do you go back for seconds for the low fat ice cream? A few weeks ago I moved house. With all my stuff packed up I spent about 2 weeks eating meals out. Plus it was a celebration with my friends and I was drinking frequently during that period. What happened was that I became less and less hungry, going down to only two meals per day. What was happening? My body was lowering my Ghrelin levels down because of the high calorie foods. Once I got settled into my new place and started eating healthy again, my appetite went through the roof. As it so happens, our perception of what we eat can determine how hungry we are.
Thoughts Affect Hunger
It can’t be denied, but what we think can have dramatic effect on the body. Just consider clinical trials where two groups of people are given either the drug or a sugar pill. It has been shown that the sugar pill can be just as effective on people compared with people that receive the actual drug.
Researchers from Yale university wanted to see if the something similar could happen with food. They wanted to see what the difference was in the body between people perceiving to eat a high calorie food compared with a low calorie food.
The hormone that the researchers were interested in was Ghrelin, the hunger hormone. Ghrelin produced in the hypothalamus and gut is secreted when the stomach is empty or when the energy balance is low. It causes us to be hungry and to eat food.
Researchers gave participants 2 shakes over two weeks. One was on the pretense that it was a 620 calorie indulgent shake. The other they told was a 140-calorie “sensible” shake. Both were actually 380 calories, The researchers got them to drink the shake and recorded their hunger as well as the hunger hormone Ghrelin. What they found was that there was a sharp decrease in Ghrelin levels in the ‘high’ calorie shake whereas the ‘low’ calorie shake Ghrelin remained flat. This means that the participants felt full after drinking the ‘high’ calorie shake and not the ‘low’ calorie shake.
There have been other reported studies where the labels on food affect the taste and preference of people. For instance, coke tastes better when it comes from a branded cup. Marketing knows this. What can get consumers is when a label has ‘lower in sugar’ to be perceived as healthy but actually is still high in sugar or other perceived healthy claims.
It is important to listen to the body when it comes to eating. The body knows how many calories that it needs to eat to eat everyday even if that means eating twice a day.
Crum AJ, Corbin WR, Brownell KD, Salovey P, ‘Mind over milkshakes: mindsets, not just nutrients, determine ghrelin response’, Health Psychol. 2011 Jul;30(4):424-9