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In the human body system, hormones are involved in nearly every aspect of health including sexual function, growth and development, mood, appetite, and metabolism. It is for this reason that hormone dysregulation – when our body releases too little or too much of a hormone – can significantly impact health, including body weight. Additionally, an imbalance of hormones involved in appetite control may lead to weight gain [1]. Several of these hormones include leptin, insulin, and sex hormones [2]. Regardless of their roles in our appetite - hunger simulation, inducing fullness, and reducing food intake - an imbalance of these hormones can lead to obesity [1,2].
Leptin is a hormone that helps your body maintain its weight in the long term. It leads to a decrease in appetite and an increase in heat generation from energy, both of which lead to a decrease in obesity. However, when an individual is overweight, leptin levels rise due to a lack of sensitivity to its effects and thus, does not have a reduced appetite which leads to weight gain [1,2].
Insulin is a hormone released by our pancreas in response to the rise in blood sugar after eating, storing excess glucose into the muscle and fat cells. In the muscle, glucose is burned as fuel or stored as glycogen. In the fat cells, glucose is either burned or converted to fat. In obesity, insulin signals are lost, and the body develops a resistance to the hormone. This is the hallmark feature of type 2 diabetes and metabolic syndrome [2,3].
Sex hormones also affect our weight:
⦁Estrogen (female hormones) triggers puberty and regulates fertility. It also affects body shape, affecting the hips and thighs. In obesity and after menopause, estrogen levels begin to change, thus changing the fat distribution. Fat will start to accumulate more in the woman’s abdominal area, which increases risk of diseases [2,3].
⦁Testosterone (male hormones) affects mood, cardiovascular health, puberty, as well as fertility. It is the hormone that encourages muscle formation and tamps down body fat. However, around the ages of 20 to 30, a man’s testosterone levels drop about 5-10% per decade. Though few studies have proven this theory, it has been shown that men with low testosterone tend to have a lower percentage of muscle and a higher percentage of fat, especially visceral fat.
Other hormones that have an effect on weight are ghrelin, thyroid, and cortisol.
Lifestyle and diet can also affect hormone levels. Diet, activity level, and chronic stress have all been linked to hormonal fluctuations. Studies show that diets rich in ultra-processed foods, added sugar, and refined carbohydrates can lead to hormonal dysregulation. Additionally, research suggests that diets with high amounts of protein and low to moderate amounts of carbohydrates may have a more favorable effect on fullness and hunger hormones than higher-carb, lower-protein diets. Diets rich in ultra-processed foods and added sugar may increase levels of hunger hormones like NPY and blunt the effects of fullness hormones like CCK. These effects may prompt overeating and weight gain. A diet high in ultra-processed foods increases exposure to endocrine-disrupting chemicals like phthalates. These chemicals have been shown to alter hormones that regulate appetite, fullness, and food preferences, as well as cause insulin resistance, all of which may influence weight gain. Insufficient rest is also associated with hormonal dysregulation. Sleep deprivation is linked to insulin and leptin resistance, and hunger hormone derangement, which may lead to increased appetite, decreased fullness, overeating, and weight gain [3].
Hormones control hunger, fullness, metabolism, and fat distribution, all of which can influence body weight. In order to manage all of these factors, it is important that we remain prudent to our body - to care for it through a healthy and balanced lifestyle.
References:
1. Kubala, Jillian. “How Do Your Hormones Affect Your Weight?” Healthline, Healthline Media, 15 Sept. 2021, https://www.healthline.com/nutrition/how-hormones-influence-your-weight-all-you-need-to-know.
2. Mandal, Dr. Ananya. “Obesity and Hormones.” News, 27 Feb. 2019, https://www.news-medical.net/health/Obesity-and-Hormones.aspx.
3. Jibrin, Janis. “Do Your Hormones Affect Weight Loss?” AARP, 6 Aug. 2020, https://www.aarp.org/health/conditions-treatments/info-2020/hormones-and-weight-loss.html.
Contributors:
Author: Georgia Sukendro
Editors: Lauryn Agron and Sara Giarnieri
Health scientist: Joanna Gudino