The Program: Objectives of Pre-Maintenance
WHAT’S THE STORY ON LOW-CARB DIETS AND EXERCISE?
Chances are you’ve heard these three statements:
- You need to eat lots of carbs to have the energy to exercise.
- High-carb diets optimize exercise capacity.
- Because Atkins is a low-carb diet, it must play havoc with your ability to be physically active.
You’ll be pleased to know that all three of these assumptions are wrong. Despite these common misconceptions by many nutritionists and athletes, the reality is that your body adapts to a low-carb diet, allowing access to your fat stores and burning more fat for fuel. In fact, these are the same desirable outcomes associated with exercise training. Being able to burn fat for energy and thus spare carbohydrate stores while exercising is a major goal of endurance athletes. From a purely metabolic perspective, the Atkins diet and exercise are highly complementary. How do we know that? Research tells us so.
Research on Cyclists
One study looked at elite cyclists who ate a diet similar to the Atkins Lifetime Maintenance option. Given their very low carbohydrate intakes, conventional wisdom would have predicted severely impaired performance. And for the first week or two, the cyclists did struggle to maintain their training schedule. Four weeks later, however, when researchers tested the amount of time it took for the cyclists to reach the point of exhaustion, the results were virtually identical to their previous performance while on a high-carb diet. There were, however, dramatic changes in fuel selection. After the four-week period, the cyclists used almost exclusively fat during exercise, making very little use of blood sugar (which remained at the normal level) and muscle glycogen (stored glucose).
Research on Weight Trainers
Atkins and weight training are highly compatible as well. In another study, overweight men followed a diet comparable to the Ongoing Weight Loss phase of Atkins while participating in an intense resistance-training program. After 12 weeks, the men showed extraordinary changes in body composition. They lost an average of 16 pounds of fat, attributable mainly to their low-carb diet. Meanwhile, their lean body mass actually increased by 2 pounds, credited mainly to the resistance training. These and other studies clearly shatter the common misconception that you need a high-carb diet to benefit from exercise.
All of this is good news for Atkins followers. Remember, though, that it can take time for your body to adapt to a primarily fat-burning metabolism. That’s why we recommend that you wait at least two weeks after starting Atkins before beginning a new exercise program or ramping up your current level of physical activity.
S. D. Phinney, B. R. Bistrian, W. J. Evans, E. Gervino, and G. L. Blackburn, “The Human Metabolic Response to Chronic Ketosis without Caloric Restriction: Preservation of Submaximal Exercise Capability with Reduced Carbohydrate Oxidation,” Metabolism 32 (1983), 769–776.
S. D. Phinney, B. R. Bistrian, R. R. Wolfe, and G. L. Blackburn, “The Human Metabolic Response to Chronic Ketosis without Caloric Restriction: Physical and Biochemical Adaptation,” Metabolism 32 (1983), 757–768.
E. E. Quann, T. P. Scheett, K. D. Ballard, M. J. Puglusi, C. E. Forsythe, B. M. Volk et al., “Carbohydrate Restriction and Resistance Training Have Additive Effects on Body Composition during Weight Loss in Men,” Journal of the American Dietetic Association (abstract), 107(8) (April 2007), A14.