# Which Food Gives More Energy To Human Body?

Food energy refers to the potential chemical energy stored within the bonds of food molecules that can be released and utilized to fuel metabolic processes in the human body (https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/food-energy). This energy comes primarily from the macronutrients – carbohydrates, proteins, and fats – that are broken down and oxidized to generate ATP, the energy currency of cells (https://en.wikipedia.org/wiki/Food_energy). The energy content of food is commonly measured in calories or kilojoules. When we eat and digest food, the energy stored within it is released and can be utilized to fuel bodily functions like muscle contraction, nerve impulse transmission, and the maintenance of body temperature.

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## Measuring Food Energy

The energy in food is measured in calories or kilojoules. A calorie is the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius. A kilojoule is the amount of energy needed to raise 1 kilogram of water by 1 degree Celsius (1). So a calorie is equal to 4.184 kilojoules.

On nutrition labels, the energy content of foods is usually listed in kilojoules (kJ) and calories. While technically a calorie refers to the amount of energy to heat 1 gram of water, food calories (also called dietary calories or kilocalories) represent the amount of energy to heat 1 kilogram of water, or 1000 grams. So one food calorie is equal to 1000 calories used in science or 4184 kilojoules (2).

The energy expenditure of physical activity is often measured in metabolic equivalents (METs). One MET represents the amount of oxygen consumed while seated at rest, which is equal to 3.5 milliliters of oxygen per kilogram of body weight per minute. Activities are assigned MET values based on their intensity and the amount of oxygen used compared to rest (3).

In summary, the energy content of foods is measured in calories or kilojoules, while the energy expenditure of exercise is measured in METs. But these units all represent measurements of energy.

Sources:

(1) https://www.betterhealth.vic.gov.au/health/healthyliving/kilojoules-and-calories

(2) https://www.mcgill.ca/oss/article/nutrition/how-caloric-value-food-determined

(3) https://www.cdc.gov/nccdphp/dnpao/multimedia/infographics/getmoving.html

## Carbohydrates

Carbohydrates are one of the main sources of energy for the body, providing 4 calories per gram (according to Otsuka). They are the preferred energy source for the brain and central nervous system. During digestion, carbohydrates are broken down into glucose which is then absorbed into the bloodstream. This glucose acts as a direct energy source for cells and tissues in the body.

As MedlinePlus states, glucose from carbohydrates is the primary fuel used by the body’s cells. After a meal, any excess glucose not immediately used is stored in the liver and muscles as glycogen. When glucose levels drop, glycogen can be broken down into glucose again for an energy source.

According to a study by Jéquier, carbohydrates from food account for about half of normal energy intake. Carbohydrates are an essential energy source supporting physical activity, brain function and central metabolism. The type of carbohydrate (simple vs complex) impacts the rate of digestion and absorption, providing either quick or more sustained energy.

## Fats

Fats provide the most concentrated source of energy in the diet. In fact, according to the Merck Manuals, “Each gram of fat supplies the body with about 9 calories, more than twice that supplied by proteins or carbohydrates.” When food is digested, fats are broken down into fatty acids and glycerol. The fatty acids are absorbed directly into the bloodstream and transported to tissues throughout the body where they can be used for energy production.

The NHS notes that “all types of fat are high in energy. A gram of fat, whether it’s saturated or unsaturated, provides 9kcal (37kJ) of energy compared with 4kcal (17kJ) for carbohydrate and protein.” This makes fat the most energy-dense macronutrient. The high energy content of fats means the body can efficiently store any excess energy from fat as body fat. This stored energy can be tapped into when needed.

Because of their high energy density, fats help sustain energy levels and have key functions related to maintaining energy balance in the body. Consuming appropriate amounts of healthy fats can provide the fuel needed to get through the day.

## Proteins

Proteins play a crucial role in providing energy to the human body. Unlike carbohydrates and fats, proteins are not a primary source of energy. However, when carbohydrate and fat intake is insufficient, the body will break down proteins for energy through a process called gluconeogenesis 1. During gluconeogenesis, amino acids from proteins are converted into glucose, which can then be used for energy.

While proteins contain 4 calories per gram like carbohydrates, relying on protein for energy is not ideal. Proteins serve many important bodily functions like building and repairing muscles and tissues, fighting infections, and carrying oxygen through the blood. Using protein for energy takes away from these vital processes. The body prefers to use carbohydrates and fats for energy and reserve protein for its primary jobs.

For these reasons, a healthy diet should prioritize adequate carbohydrate and fat intake to spare protein for its unique purposes. While protein can provide energy in a pinch, it is not the body’s preferred energy source. Consuming balanced amounts of carbohydrates, fats and proteins ensures proteins are available for their essential biological roles.

## Vitamins and Minerals

Vitamins and minerals play crucial roles in energy production and utilization in the body. They act as cofactors for enzymes involved in cellular respiration and metabolism. Deficiencies in certain vitamins and minerals can lead to reduced energy levels and fatigue.

B vitamins like B12, B6, and folate are involved in energy metabolism and red blood cell production. B12 deficiency can lead to anemia and fatigue (Tardy, 2020). Magnesium plays a role in ATP production and over 300 enzyme systems. Low magnesium is associated with fatigue and weakness (Tardy, 2020).

Iron is needed to make hemoglobin to transport oxygen. Iron deficiency can result in impaired oxygen delivery. Vitamin C aids iron absorption. Zinc deficiency can also cause lethargy and weakness.

Getting adequate vitamins and minerals can help maintain optimal energy levels and prevent fatigue. Supplementation may be beneficial for those with deficiencies.

## Caffeine and Energy

Caffeine is a stimulant that can provide a temporary boost in energy and alertness. It works by blocking adenosine receptors in the brain, which normally make us feel tired. When caffeine blocks these receptors, it increases activity in the brain and nervous system, leading to the release of adrenaline. This stimulates the heart rate, increases blood pressure, and gives the sensation of having more energy 1.

Caffeine doesn’t actually provide energy itself – it just makes us feel more alert by changing how our brains and bodies function. The energy boost is temporary and only lasts for a few hours before adenosine receptors become active again. Consuming too much caffeine or consuming it late in the day can disrupt sleep cycles and cause jitteriness or anxiety 2.

While caffeine can provide a short-term energy boost, it does not give our bodies sustainable energy. A balanced diet with nutrient-dense foods is key for maintaining energy levels throughout the day.

## Hydration and Energy

Water is essential for generating energy in the human body. Proper hydration allows cells to effectively produce ATP, the key source of energy at the cellular level. When the body is dehydrated, it struggles to carry out basic metabolic processes that require water as a solvent and transportation medium.

Studies show that even mild dehydration of 1-2% loss in body weight results in reduced physical and mental performance [1]. This includes decreased endurance, increased fatigue, altered thermoregulation and cardiovascular strain. Severe dehydration can be life-threatening.

Water’s importance in cellular energy production relates to its high heat capacity and hydration energy. The hydration shells around proteins and cellular components allow them to maintain their shape and function. Hydration energy also stabilizes charge separation needed for metabolism.[2]

By supporting vital biochemical reactions and transport, proper hydration provides cells with the water and energy they need to perform optimally. Dehydration directly reduces disponible energy at the cellular level. Maintaining adequate water intake and preventing dehydration are key to generating energy.

## Lifestyle Factors

Our daily lifestyle habits have a major impact on our energy levels. Exercise, sleep, and stress management play key roles.

Regular exercise provides a energy boost and can help sustain energy throughout the day. Aerobic exercise like walking, running, biking increases heart rate and promotes blood flow, getting oxygen and nutrients to our cells more efficiently. Strength training builds muscle mass, which boosts metabolism. Studies show just 30 minutes per day of moderate exercise can significantly increase energy (1).

Getting adequate sleep, around 7-9 hours per night for adults, is vital for feeling energized. Sleep allows the body to repair muscles and tissues, consolidate memories, and release hormones that regulate appetite and energy use. Chronic sleep deprivation is linked to fatigue, impaired concentration, and increased risk of illness (2).

Managing stress properly helps avoid energy drains. Chronic stress causes elevated cortisol levels, which disrupt sleep, mood, immunity and lead to burnout. Relaxation practices like meditation, yoga, deep breathing, and getting social support can reduce stress and boost energy (3).

Overall, those who exercise regularly, get sufficient sleep, and employ stress reduction techniques have more sustainable energy levels.

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## Conclusion

In summary, while all macronutrients provide the body with energy, fat provides the most calories per gram. However, the optimal energy source depends on the situation and dietary needs. Carbohydrates offer quick, short-term energy while protein and fat provide more prolonged energy. When combined in balanced nutrition, carbohydrates, fats, and proteins all play important roles in providing the body with energy. Several other factors like caffeine, hydration, vitamins and minerals also influence perceived energy levels. Ultimately there is no single “best” energy food, but rather the key is eating a varied diet with a diversity of whole foods. This provides the body with a range of macronutrients, micronutrients and phytonutrients needed for optimal health and energy production.