How Diet Influences Key Hormones and Metabolism


Recently, we discussed the complex interplay of key hormones and metabolism when different physical activity strategies are employed. Additionally what we eat has the power to alter metabolism via the endocrine pathway. Depending on the type of food consumed, it may be burned, stored as fat, or utilized in cellular regeneration. What food becomes once it is consumed will depend on the food’s composition what the body needs.

Macronutrients and Metabolism

Foods that are high in saturated fats and refined sugars eaten in excess will be processed into energy storage to be used later for energy output during activity. In contrast, a nutrient-dense food high in protein eaten in moderation will be used for energy conversion, tissue replacement, and rebuilding; the food is utilized to rejuvenate and replace the body’s active tissues.

Protein, carbohydrates, and fats impact hormonal responses in different ways when introduced to the digestive system. Certain amino acids in high concentrations from complete proteins can increase growth hormone production, which in turn raises metabolism.


Since hormones are made from proteins, a diet with inadequate protein intake may lack the raw materials to rebuild the body or even manufacture the hormones that initiate such actions of rejuvenation. Furthermore, ingesting adequate protein will help suppress ghrelin–the hunger hormone–and increase leptin—the satiety hormone, and maintain this balance throughout the day. Furthermore, some studies indicate that eating a high protein diet (30% of calories) resulted in a regulated energy balance and lower hunger levels when compared to those on an adequate protein diet (10% of calories) even though energy intake remained the same. In other words, the high protein group expended more energy throughout the day.


Carbohydrates can influence insulin to a greater or lesser extent depending on the source and type of carbohydrates. Insulin is a hormone that affects storage and uptake of nutrients. Refined, simple carbohydrates enter the circulatory system rapidly from the digestive tract and quickly elicit a large release of insulin. This signals the rest of the body to pull blood sugar (glucose) from the blood. If the glucose depots (muscles and liver) are full, it will be converted to fat and stored in the adipose tissue.

Hormones Appetite & Hunger
Hormones appetite & hunger. Human endocrine system. Incretin, ghrelin, leptin and insulin

This roller coaster effect of insulin feedback in response to elevated blood glucose causes hunger mechanisms to be activated as well. When too much insulin is secreted, blood sugar levels drop too low and the hunger hormone ghrelin is released. The more insulin secreted in the presence of high blood glucose the more the body will store the energy in the cells and create a vicious cycle of eating.

Complex carbohydrates on the other hand, take longer to process in the digestive tract and have a much slower absorption rate into the bloodstream, hampering such a roller coaster effect. Controlling insulin with diet choices makes it easier to control hunger, storage, and the food energy conversion rate.


Years ago fat was thought to be the main culprit to obesity, but now we better understand the role of fat in the diet. Science is uncovering which fats are actually of benefit to a healthy metabolism. Without dietary fat, one cannot absorb fat-soluble vitamins (A,D,E,K) that are crucial to almost every metabolic action in the body. Also, there has been recent scientific research that indicates that certain fatty acids (CLA, GLA, omega 3’s, etc.) have hunger-busting, thermogenic, and even anabolic properties. It is not well understood how these fats perform these actions, but they are well-documented and now widely utilized for health aspects.

Balanced Nutrition for the Win

Balanced nutrition provides construction materials for replacement tissues and body systems and fuel to be converted to energy. It also provides catalysts (vitamins, minerals, trace elements, etc) for the billions of chemical reactions that are taking place all the time, and providing protection from the abundance of free radicals that we are in constant production and contact with from our activities and environment.

The diet-exercise-hormonal link is well established. It should also be noted that the absence of regular exercise and optimal nutritional intake is detrimental to the body and deregulation of these hormonal pathways. Chronic inactivity and poor dietary choices can lead to premature aging and disease.


NFPT Publisher Michele Rogers, MA, NFPT-CPT, manages and coordinates educational blogs and social media content for NFPT. She’s been a personal trainer for 20 years with a lifetime passion for all things health and fitness. Her mission is to raise kinesthetic awareness and nurture a mind-body connection. After battling chronic lower back pain and becoming a parent, Michele aims her training approach to emphasize corrective exercise and pain resolution. She holds a master’s degree in applied health psychology from Northern Arizona University. Follow Michele on Instagram.