What role does the brain play on satiety?

Have you ever wondered why eating is more often driven by the little voice in your brain, or the anticipation of how good the food will taste in your mouth, rather than by the loud rumblings of your empty stomach? Since when did emotional eating became more important than the physical need of eating? The only answer to why we should eat is because we are hungry, but it is not that simple.

Scientific rationale behind food cravings

“Finish your meal if you want dessert”. Does this habit-forming sentence rings a bell? For parents, this may be the most convincing thing to say to make a child eat their ‘healthy’ food on their plate. The downside in this pattern is that it conditions the brain to expect a reward after the smallest effort, and to eat even when not hungry. Specifically, it forms associations between eating, past reaching the point of satiety, and cleaning off your plate, to a reward – a desert high in sugar and fat.

Wanting dessert even after a satisfactory meal is also explained by the sensory specific satiety, or ‘dessert stomach’. This studied phenomenon confirms that even when eating food to satiety, there is an anticipation of the enjoyment of a new taste, which overrides the satiety signals. It makes dessert so appealing it generates a new appetite — hence “dessert stomach”.

Food cravings arise from interwoven psychological, hormonal, and physiological reasons

• Psychological: Emotions are taking control over the physical need
  • Sometimes, an emotional signal triggers a behavior: you had a bad day; you think “I deserve a glass of wine”. Habits can also come from the positive emotion felt in childhood by associating specific treats to specific moments. In adulthood these habits are reiterated because they are comforting – ice cream after the game, popcorn at the movies, chocolate spread on bread for breakfast, etc. Or certain foods bring back positive memories, like when you had a special permission to eat sweets, otherwise not allowed, in a birthday party during childhood, and this feeling of happy transgression hits a sweet spot in your brain every time you eat candies in adulthood. All these emotional links to food makes you enjoy eating, even when you are not necessarily hungry. If you have these habits, you are not alone, 45.7% of consumers worldwide stated that their main challenge for losing weight is the fact that they enjoy treats and moments of indulgence.

• Hormonal: The messenger molecules working together to increase or decrease appetite and fat storage
  • Hormones play many different roles to trick people into eating too much of the wrong stuff. Sugary processed foods may trigger the release of the ‘feel-good’ neurotransmitter, dopamine, in the brain’s reward center. Deprivation and starvation cause the body to produce lower levels of leptin, an appetite suppressing hormone, and more lipoprotein lipase, an enzyme that increases fat storage. Also, the ghrelin, also known as the ‘hunger hormone’ sends a message to the hypothalamus when the stomach is empty, as a reminder to eat. When we deprive the body of food, it makes it work harder to hold onto fat, a basic survival mechanism. In periods of under-eating or caloric restriction, the hormones send a distress signal creating a physiological urge to eat, more often high-fat, high-sugar foods because they are the most caloric dense. 

• Physiological: the body’s physical response to physiological trigger like stress
  • Stress, anxiety-like symptoms, lack of sleep, unstable mood, periods, pregnancy… Regular physiological factors can have an impact on physical functions. From a physiological standpoint, stress causes the adrenal glands to release a hormone called cortisol. This spike in cortisol puts the body in a state of high metabolic stimulation, because the stress makes the body think it needs to replace all the energy we used to fight off the wolf or lion, the ancestral causes of stress, instead of today’s meetings and presentations. Consequently, the appetite is intensified and cravings for foods high in carbs and fat emerge. People who don’t get enough sleep tend to crave foods that are sweet, salty and/or starchy to help boost their energy levels.

Control the brain to better control weight management efforts

Weight loss and weight maintenance programs should be comprehensive, combining nutrition and physical activity interventions with the inclusion of behavioral strategies. But even with all the goodwill in the world, in conjunction with the best diet plan and the best training plan, efforts to lose weight can be defeated by what is going on in the brain, therefore this aspect remains an important factor for supporting a healthy metabolism during a weight loss program.

New breakthrough study shows L. rhamnosus HA-114 supports weight management efforts

Lallemand Health Solutions’ probiotic strain L. rhamnosus HA-114 improves eating and mood-related behaviors in otherwise healthy adults with overweight during weight loss. In a new study, scientists have shown a strong potential role of this probiotic strain to restore the psychological balance and support weight management efforts during a calorie-restricted diet, thanks to its action on the brain-gut axis. Significant results compared to placebo group or baseline have been seen in eating behaviors, reducing the urge for binge eating, food cravings and decreasing perceived stress and anxiety linked to the fear of adhering to the diet.

 

References

https://www.webmd.com/diet/features/the-facts-about-food-cravings#1
https://www.medicalnewstoday.com/articles/318441
https://brainworldmagazine.com/crave-science-behind-food-cravings/
https://www.huffpost.com/entry/so-theres-a-scientific-reason-why-we-always-have-room-for-dess_n_61087607e4b0999d2084f657
https://www.hsph.harvard.edu/nutritionsource/cravings/
https://www.sciencedirect.com/science/article/pii/S2212267214010557