Hormones for fat loss
Jacky, HK BioTek Intern
Fat loss might sound easy for someone while being completely opposite for another. Some blame the fact that some people are simply born to be fat while some are born slim and skinny.
To some extent, this statement is true for the fact that the response to hormones varies among the bodies of different people. However, obesity and overweight are more likely to be induced by habits in one’s diet, which influences the hormonal balance in our bodies. The following would be the hormones regulating your body fat level.
Leptin is a classic in body weight management. In short, the secretion of leptin from the hypothalamus creates satiety after we eat. Therefore, leptin is known as the ‘thinning hormone’ of our bodies. It is released by the fat cells in our body, and the more fat cells exist in our body, the more leptin is secreted. Yet, eating too much can cause our bodies to be desensitized to leptin, delaying satiety occurrence and leading to obesity in the long term, as our bodies are becoming more insensitive to leptin as we consume more.
Ghrelin comes as the opposite of leptin, being responsible for hunger upon release. The secretion of ghrelin makes us feel hungry, and obese people tend to have a greater sensitivity toward ghrelin.
Insulin acts by converting what we eat into energy. It converts the carbohydrate we absorbed glucose, into an energy reservoir of our muscles, glycogen. Having large and frequent meals induces insulin resistance in our bodies, as our liver becomes desensitized to insulin, leaving the glucose in our blood not being converted to glycogen effectively. This excess glucose will be otherwise converted to body fat.
Then, should calorie restriction be the absolute solution for fat loss? The answer is no. Research has shown that calorie restriction under Basal metabolic rate (BMR) would lead to a lower BMR in the long term, whereas BMR represents the energy required for your daily vital activity, such as breathing and heartbeat. It means calorie restriction will make fat loss harder and harder in the long run.
Moreover, solely diet restriction without exercise pulls muscle away from your body. Exercise is crucial in creating a higher energy expenditure in your body, such that you can lose weight while eating the same amount of food you are eating, or not having an aggressive restriction in your diet. It also stimulates hormones such as IGF-1, which helps preserve muscle during weight loss.
Additionally, the hunger hormone ghrelin rises upon calorie restriction due to hunger, which makes the diet restriction even harder to complete.
Thus, we must couple exercise with moderate diet restriction to induce fat loss, while maintaining wellness as stress has been recognized as one factor for fat gain, as it induces a hormonal imbalance in our body. Extreme calorie restriction, if it is to be implemented, must be under supervision by registered dietitian or practitioners.