Fat as fuel

Let’s review:

1. The body needs lots of energy for marathon training.

2. Food is fuel.

3. Fuel produces energy.

4. Muscles use carbohydrates, fat, and small amounts of proteins for fuel.

The human body never ceases to amaze me. Despite our best efforts to wreck it with fried pickles and beer, the body is an incredibly efficient machine. Endurance training – i.e., marathoning and long runs – helps to condition the body to burn more fat. Specifically, marathon training promotes more efficient fat burning and less reliance on burning carbs by burning glycogen stores more slowly over a longer period of time.

During long runs, the body relies much more on fats than it does on shorter runs. The body does this to prevent glycogen depletion. Think of the body as a hybrid vehicle, burning two forms of energy – in this case carbohydrates and fat. It is a perfect example of energy efficiency.

Running 6 miles or more is great for fat burning because the body seeks to run more efficiently by burning more fat. Naturally, the more long runs you do, the more fat you burn. Not to mention, a responsible diet with acceptable levels of fat, combined with regular calorie burning, which is done daily – or almost daily – during shorter runs, leads to increased fat burning.

The curious exception is fuel used for speed. The faster you run, the more carbs you burn relative to fat. Fats use oxygen less efficiently that carbs, so muscles rely more heavily on carbohydrates than fats when you’re burning rubber.

One should still consume fats wisely. That means consuming meats that are leaner, dairy products lower in fat content, and a responsible diet of fat. What’s “responsible”?The American Heart Association recommends 30% of our calories to come from fat, which is not really that hard to do. In a nutshell, eaters can make great progress by avoiding fried foods and processed snacks.

To shed light on the mystery of fats, it is good to understand what they are and what they do.