Why Do Fats Provide More Energy for the Body?

Among the three main macronutrients—carbohydrates, proteins, and fats—fats stand out as a long-lasting and sustainable source of energy, helping the body maintain effective functioning throughout the day. So why does consuming fats increase energy more than carbohydrates and proteins? To understand this better, we need to look into the metabolism mechanisms and physiological roles of fats in the body.

1. What Are Fats, and What Role Do They Play in the Body?

Fats are an essential component of the human diet. Essentially, fats are organic compounds composed of fatty acids and glycerol. Fats not only play a role in providing energy but also participate in many other biological functions, including:

• Long-term Energy Storage: Unlike carbohydrates, fats can be stored as adipose tissue and provide energy for the body over extended periods. When carbohydrate sources are depleted, the body shifts to using fats as a primary energy source, helping maintain activity, especially in situations like fasting or prolonged physical activity.
• Supporting Cell Functions: Fats are a key component of cell membranes, helping maintain cellular integrity and function.
• Insulation and Protection: Subcutaneous fat and fat surrounding organs help retain warmth and protect the body from physical damage.
• Vitamin Absorption: They enhance the absorption of fat-soluble vitamins such as vitamins A, D, E, and K.
• Participating in Metabolism: Fats help initiate essential chemical reactions in the body, influencing growth, reproductive function, and other aspects of metabolism.

In summary, fats are not only a rich energy source but also play an essential role in many biological functions of the body, from maintaining cell structure to supporting the development and functioning of organs. Therefore, incorporating a reasonable amount of fats into the diet is very important for overall health.

2. Why Do Fats Provide More Energy Than Carbohydrates and Proteins?

When discussing the energy that the body receives from food, we often refer to the unit of calories. Each gram of carbohydrates and each gram of protein provide about 4 calories. However, each gram of fat provides up to 9 calories—more than double that of carbohydrates and proteins. This makes fats a significantly higher energy source compared to the other two nutrients.

Additionally, fats have an excellent capacity for energy storage. While the body can only store a limited amount of glycogen (the storage form of carbohydrates) in the liver and muscles, fats can be stored as adipose tissue throughout the body, providing a long-term energy source when needed.

3. The Mechanism of Metabolizing Fats into Energy

Consuming fats increases energy by participating in the production of energy in the form of ATP (Adenosine Triphosphate), which helps maintain activity over long periods, especially when carbohydrates are limited. This complex metabolic process occurs primarily in the cells. The mechanism of fat metabolism is as follows:

When the body needs energy, especially during prolonged physical activity, triglycerides—the main storage form of fats—are broken down into fatty acids and glycerol. This process is called lipolysis.

Once released, glycerol enters the glycolytic pathway in the form of DHAP (dihydroxyacetone phosphate) to generate energy or be converted into glucose, serving the energy needs of the body. Meanwhile, fatty acids are transported into the mitochondria of the cells, where they undergo beta (β)-oxidation. Here, fatty acids are converted into acetyl CoA, an important molecule that participates in the Krebs cycle. In this cycle, acetyl CoA is used to produce ATP, the primary energy unit that the body utilizes for vital activities, helping maintain sustainable energy, especially during prolonged activities.

Additionally, if there is an excess of acetyl CoA or insufficient glucose from the diet, it will be converted into ketone bodies, providing an alternative energy source in the absence of glucose, such as during fasting or diabetes. This process not only allows the body to maintain continuous activity but also demonstrates that fats play an essential role in sustaining energy, enabling the body to function effectively even under carbohydrate scarcity.

4. Benefits and Limitations of Using Fats as an Energy Source

Consuming fats increases energy and provides a rich reserve for the body, helping to maintain long-lasting energy. However, fat metabolism takes longer, and excessive consumption can pose health risks. Understanding these benefits and limitations will help you use fats effectively in your diet.

Benefits: 

• Long-lasting Energy: Thanks to their excellent storage capacity and slow metabolism, fats help maintain stable energy levels over extended periods.
• High Energy Content: A small amount of fat can provide a significant number of calories, reducing the need for frequent consumption.

Limitations: 

• Slow Metabolism: The body takes longer to break down and utilize fats, so the process of converting fats into energy is slow, making fats not the quickest way to boost energy. In contrast, carbohydrates can be rapidly metabolized, providing immediate energy for high-intensity activities over short durations.
• Health Risks from Excessive Consumption: While fats provide high energy, consuming too much can lead to overweight and related diseases such as diabetes, cardiovascular issues, and hypertension.

To sustainably increase energy, it is essential to maintain a balanced and reasonable diet. Using fats to provide energy is an effective method if you understand its metabolic mechanisms and consume them in a controlled manner. More importantly, you need to proactively care for your health early on to maintain fitness, mental clarity, and longevity.

Taking care of your health early and monitoring your nutrition will help you lead a healthy and long life. If you encounter any health issues, understanding and seeking early treatment solutions are essential for living healthily, with clarity of mind, and longevity.

References: biobeat.nigms.nih.gov – msdmanuals.com – bio.libretexts.org