ORGANIC COMPOUNDS & BODY ENERGY

Organic Compounds & Body Energy

Organic Compounds & Body Energy

Introduction

Diet composition is known to influence energy intake and body-weight changes in rats and humans. However, the results are contradictory, and it remains unclear what the relative importance of protein, carbohydrate and fat is. Moreover, the influence of different physiological (genotype, gender, insulin resistance) and feeding conditions (degree of energy restriction, duration of feeding a specific diet) is not yet established.

In order to achieve a reduction in body fat, weight-reducing diets must attain a negative energy balance. An increase of the protein content of diets at the expense of carbohydrates has brought such an advantage in some feeding studies. Further, there is increasing evidence of higher thermic response following protein ingestion as compared with carbohydrates or fat. The mechanisms for the influence of dietary protein on thermic effects are not clear and are controversially discussed. Uncoupling protein homologues (UCP1-3) have been shown to lower mitochondrial membrane potential in several mammalian cell expression systems, suggesting uncoupling activity of the respiratory chain from ATP synthesis by generation of a proton leak. In consequence, respiration rate relative to a certain ATP production can increase and energy is wasted as heat. Further, expression of UCPs is known to be influenced by factors such as long-term high-fat (HF) or high-protein (HP) intake. We could show an organ-specific inverse association of UCP gene expression with feed energy efficiency and a positive association with nighttime energy expenditure (EE) and oxygen consumption[13] K.J. Petzke, M. Friedrich, C.C. Metges and S. Klaus, Long-term dietary high protein intake up-regulates tissue specific gene expression of uncoupling proteins 1 and 2 in rats, Eur J Nutr 44 (2005), pp. 414-421. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (8). Increasing the protein content in an HF diet delayed the development of obesity and improved glucose homeostasis in a mouse model of diet-induced obesity.

Energy Content

1 gram of protein

17 kJ

1 gram of fat

37kJ

1 gram of carbohydrates

17kJ

Fats Converted into Energy

The primary reason we need to eat food is to provide fuel for the body. This fuel comes from the breakdown of carbohydrates, proteins, and fats. To explain it simply, food is broken down to produce energy, and it takes many chemical processes for that to occur. Molecules are removed, heat is produced, but basically all that is left in the end is water, carbon-dioxide, and energy. But it's far more complicated than that. Carbohydrates, proteins, and fats, each get converted to energy but each take a different path. Before I start on how fat is burned (or broken down), let me first explain a few key terms in the process of converting food to energy:

* ATP: Adenosine Tri-phosphate is energy. It's what the body uses as fuel at the cellular level. It can be produced using oxygen (aerobic), or without the presence of oxygen (anaerobic). * Glycolysis: An anaerobic process where carbohydrates is converted to pyruvic acid.

* Pyruvic Acid: If oxygen is available it is converted ...