How food controls our body's capacity to burn fat

BY JULIE SEAMER
TUESDAY, NOVEMBER 11, 2008

It is common knowledge that food consumed to excess can form body fat. And in an ideal world we could provide our bodies with precisely the amount of nutrients required for energy and metabolic requirements; no more. Unfortunately this isn't always easily achieved. Carbohydrates tend to dominate our eating preferences, along with unhealthy fats and food additives. The ongoing question is: how can we balance our diets to ensure body fat reserves are kept to a healthy level?

It is important to establish how fat is formed. The primary function of fats is for energy production. Their conversion is a simple process involving the absorption of triglycerides (the major components of all the saturated and unsaturated fats and oils we consume) for conversion into units of energy for fuel. Generally, the energy that is eventually produced within the body is proportional to the size of the triglyceride (long or short chain). These fats carried to every tissue cell in the body via the bloodstream are manufactured for energy. However, there is one vital factor that can influence this process- the ingestion of carbohydrates.

When we eat a diet high in carbohydrates, the body will choose to access glucose at the expense of triglycerides. Triglycerides not absorbed by cells are treated as being surplus and are consequently taken into fat storage cells. Normally, these fat stores would be released for energy production when food is in short supply or energy requirements increase. Unfortunately this simple mechanism is complicated when the body has an over-supply of carbs.

Carbs supply the body with energy too (albeit comparatively limited energy). When ingested, sugars (from carbohydrates) are immediately converted into glucose. If activity levels are low or the body has excess glucose, the liver converts this energy into fat, to join triglycerides from ingested fats (because the body can only store limited amounts of glucose and glycogen but seemingly limitless amounts of fat). Carbs turn into glucose which, if not burnt, will suffer the same fate as excess fat and by absorbed into fat cells and stored as triglycerides.

Protein also forms body fat when consumed excessively, but it is far less of a contributor to weight problems.

The important message is this: the body supplied with a high carbohydrate diet is in a state of constant fat formation, effectively blocking the release of stored fat for energy. That is, glucose has a suppressive effect over stored fat. The problem with this: as an energy source, glucose is much lower in energy production resulting in early fatigue; a sensation most of us have become all too familiar with. And when active cells are denied their fill of amino acids and triglycerides (because of glucose dominance), the body continues to get fatter.

As with all active muscle cells, fat cells can not absorb glucose without the help of insulin. However, when large quantities of blood glucose exist, the influence of insulin getting the glucose into fat cells is prolonged, effectively blocking the outward release of energy-ready triglycerides which have been waiting in storage. Even during physical activity, triglyceride release is severely hampered and the body is forced to rely entirely on glucose and glycogen for energy.

The trick to shifting the body into fat burning mode isn't just a matter of changing diet but of course this is primarily important. While it can take time to reverse the body's tendency to rely on glucose instead of stored triglycerides (sometimes up to a year!) research shows that the body responds to heavy exercise by using more stored fat and less glucose in energy production. This shift is supported by several key hormones and enzymes:

Glucagon, citrate, growth hormone and lipoprotein lipase.

The message about the body and it's ability to burn fat is this: a person who has consumed a diet high in carbohydrate for any extended time will burn glucose for energy predominantly, even when under conditions of a heavy load. The average person can however increase their fat burning capabilities at least by 50%, by consuming a balanced diet of proteins, fats and carbohydrates for several months. Full fat burning potential (of around 90%) of total body energy many not be reached for up to a year, but it is a goal worth striving for; rebalancing your metabolism to optimal state for a leaner, healthier, happier you!

A very effective tool to help you attain this is the Aussie Bodies PCF calculator. Measuring your individual protein/carb/fat requirements this guide can help fast-track your journey, ensuring you get the most out of your diet & your well-being.

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