Scientific Research
Carbs essential to strength, study shows
According to a new study from researchers at the University of Connecticut, exercisers who switched from a carb- and protein-balanced nutrition plan to a "ketogenic diet," characterized by very low carbs (about 8 percent of total calories) and high amounts of protein and fat, experienced a 7 percent to 9 percent reduction in peak muscular power over a period of six weeks. The ketogenic plan, the researchers found, also negatively impacted the athletes' cardiovascular fitness, causing a 6 percent decrease in VO2 peak over the study period.
These results shouldn't come as a surprise given that carbohydrates are the most important energy source for exercising muscles and are the only food that can be used for anaerobic energy needed for weight training. Carbohydrates are also the most efficient fuel for aerobic exercise in that they are able to produce energy at a rate three times faster than that of fat and require less oxygen to do so.
Optimal exercise performance, numerous studies have shown, is best fueled by maintaining adequate stores of carbohydrates (glycogen) in muscles and liver, which is best achieved through carbohydrate- and protein-balanced eating.
Vitamins/minerals found lacking in low-carb eating
People concerned with optimal intake of the important vitamins and minerals should steer clear of the popular no-/low-carbohydrate plans and stick with basic, balanced nutrition, according to results of a new study presented before 12,000 scientists at the 2003 Experimental Biology conference in San Diego.
In her investigation, Beth Zupec-Kania, R.D., C.D., a dietician at the Children's Hospital of Wisconsin, analyzed a three-day very low-carbohydrate diet, providing 1,250 calories a day, for vitamin and mineral content. Zupec-Kania notes that nutrient-dense foods were purposely selected for the study to optimize results. Still, of the 24 micronutrients evaluated, disturbingly, 19 were below the Dietary Reference Intakes (DRIs).
Worse, 11 essential micronutrients were provided at less than 50 percent of the DRIs. These include thiamin, folate, pantothenic acid, calcium, copper, iron, magnesium, manganese, molybdenum, selenium and zinc.
"A selection of less nutritionally dense foods would have resulted in even lower intakes of these nutrients," Zupec-Kania says.
Micronutrient deficiencies, especially ones as severe as those noted in this study, are serious and carry major health implications, new research is showing. According to Dr. Bruce Ames, a professor of molecular and cell biology at the University of California, Berkeley, vitamin and mineral deficiencies can lead to DNA damage. In fact, in his research, Dr. Ames has found that cells lacking vitamins and minerals suffer DNA and mitochondrial damage similar to that caused by irradiation (e.g., excessive X-rays). This damage, he says, could cause you to age prematurely and could lead to cancer and degenerative diseases such as Alzheimer's and Parkinson's. "Inadequate intake of essential vitamins and minerals might explain the epidemiological findings that people who eat only small amounts of fruits and vegetables have an increased risk of developing cancer," he says.
