In part one of this series I gave you a little bit of bad news when I explained how dieting is hard and how our body’s reaction is to make sure that we maintain homeostasis, keeping everything with normal conditions and not losing weight. If you have a cat you’ll probably know that he or she likes things to stay the same, they don’t like radical changes to their environment. The human body works in the same way, keeping everything stable so that it keeps working perfectly. There are some hormones that play an especially important role in this, including insulin, leptin and ghrelin.
All of the hormones in the body work like messengers whose purpose it is to keep us alive and healthy. But how can we trick them and win the battle for successful weight loss? For this you need to know enough about them so that you can develop the correct strategy to win the game. And that’s really what it is — it’s not a war, it’s a game, and if you know what to expect then you can make a plan that will let you win.
Let’s start by looking at two hormones, leptin and ghrelin, which are responsible for satisfying our hunger.
Leptin is a peptide hormone that is secreted by fat tissue (adipose). The amounts that are secreted depend on how much fat you are carrying. Leptin sends a signal to the central nervous system and the hypothalamus then tells the body when it’s satisfied and thus maintain high fat levels in the body. Leptin helps decrease our food intake, it increases our metabolic rate, inhibits the release and synthesis of insulin and increases activity levels. Leptin levels are not affected by one single meal, it can take feeding and fasting for several days to have an effect on them. This may sound a little awkward and when you have excess body fat you should not feel hungrier — although most people who do have excess body fat feel much more hungry. The reason for this is that continuously consuming excess calories and not paying attention to the signals telling us that we are satisfied can cause leptin resistance. Leptin is then still secreted, however the brain does not respond. This increases hunger and decreases the metabolic rate, the body then enters starvation mode and starts to preserve energy, and you will gain weight even if you are eating less calories than before.
Another hormone is ghrelin, which signals the brain to feel hungry and plays an important role in body fat levels and regulating calories. Ghrelin is a peptide hormone secreted primarily in the stomach when it is empty, although also by small intestine, pancreas and the brain. Ghrelin is a hormone that increases growth, cortisol, prolactin secretion and also adrenocorticotropic hormone (ACTH) which triggers the pituitary glands to release cortisol. Ghrelin levels will lower shortly after a meal and its primary role is to regulate appetite, so if you are on a diet your ghrelin levels are mostly higher which will very much challenge your diet. It can also have effects on sleep, behavior, taste sensation and carbohydrate metabolism as well.
If after reading this you feel disheartened then don’t worry, you can definitely still win. However, it is important that you minimize or ideally not consume any industrial ultra-processed foods. They tend to make us want to eat more and more and more but they are not supplying the body with enough nutrients, instead they contain preservatives and additives and they make sure to make you addicted so that you will buy them again. So calories are definitely important, however if you want long-term and successful weight loss then you need to focus on high quality and nutrient dense foods that will keep all of your hormones are happy and healthy.
Part 3 of this series is all about the most famous hormone, insulin!
“Losing Weight: A Battle Against Fat And Biology”; https://www.npr.org/sections/health-shots/2011/10/31/141794801/losing-weight-a-battle-against-fat-and-biology
“Ghrelin enhances in vivo skeletal muscle but not liver AKT signaling in rats”; https://pubmed.ncbi.nlm.nih.gov/18070752/
“Effects of weight change on plasma leptin concentrations and energy expenditure”; https://pubmed.ncbi.nlm.nih.gov/9360521/
“What Is Ghrelin? All You Need to Know About This Hormone”; https://www.healthline.com/nutrition/ghrelin