Fat = The Superior Fuel Source

What may come as a surprise to most, is that fat is a FAR BIGGER energy source than carbohydrates. All you have to do is take a quick look at any exercise physiology literature and the fuel availability from fat is nearly 40 times that of carbohydrate storage (blood, muscle, liver):


Though conventional wisdom tells us we need carbs for energy, it’s clear that the fat tank is significantly larger. The problem is, the majority of the population never accesses it, because they’ve become accustomed to relying on carbohydrates.

Keto-adaptation – or restricting carbohydrates to a point where stored fat becomes the predominant fuel source – is not only ideal for improving your health and body composition, but it gives you the ability to tap into this GIANT alternative fuel tank.

Famous Arctic explorer, Frederick Swatka, wrote about his adaptation to an Inuit Diet (90% fat and protein) and his enhanced ability to withstand ‘prolonged sled journeys,’ in The Long Arctic Search

Ironically, restricting carbohydrates (glucose) to access the fat-tank may be the ideal solution for long distance endurance athletes, who have been instructed to ‘carb-load’ and ‘carb re-load’ their entire lives. Generally, this is prescribed to avoid ‘hitting the wall,’ which is the point where all glucose and glycogen is depleted, and unless they slam back a PowerGel or Gatorade, their race day is over.

Alternatively, an athlete that’s adapted to running on fat (ketones), either skips the wall and makes a smooth transition to the bigger better fuel tank, or burns fat right from the starting line.

  • In 1983, researchers in the journal of Metabolism found that “aerobic endurance exercise by well-trained cyclists was not compromised by four weeks of ketosis.”
  • In 1996, Peter J. Horvath and colleagues found that “runners who consumed the fattiest diet used their stored energy more efficiently than they did when on the lowest-fat diet.”

Now, I’m not going to tell you to run long distances, as I think you know my thoughts on that. The point, is that even if you did, you’d likely go further than your carb-loaded friends.

Famous low-carbohydrate researchers, Stephen Phinney and David Volek, have been producing research for years showing that the fat (ketone) tank provides far more fuel for both daily activity and endurance exercise. The only challenge they note, is that a proper 3-4 week fat- or keto-adaptation period is required. Without proper transition time, endurance athletes fail to access the fat tank, as their body is only familiar with utilizing carbohydrates. They wind up hitting the wall sooner than their carb-loaded counterparts, and researchers tend to quickly conclude that ‘carbs are better.’  Had they been given enough time to adapt to using stored fat and ketones for fuel (like the participants in the many of Phinney and Volek’s studies), they would not have hit a wall, and more than likely out-lasted the carb-burners.

Not surprisingly, the same keto-adpatation period is necessary for strength performance:

Male gymnasts on a short-term low-carb diet had reduced performance the first few days (during adaptation), but over time, strength and power was improved.

Without a proper transition to ‘fat-burner’ because of a consistent supply of dietary carbohydrates, there’s no need for your body to burn fat as fuel. And as discussed in Live It NOT Diet!, this doesn’t happen overnight.

The good news is, once you become a fat-burner, the energy reserves our plentiful, the health improvements are notable, and the fat loss is phenomenal.

Average fat loss for the gymnasts (who were relatively lean to begin with) was 4.4lbs in only 4 weeks…with NO reduction in muscle mass.

Stay Lean!

Coach Mike


It's Ketosis NOT Ketoacidosis

You Don't Need Carbohydrates For Energy

Low Carb = Increased Fat Burning & Insulin Sensitivity