While conventional diet wisdom preaches the virtues of eating breakfast every day and never skipping meals, medical experts today say skipping breakfast and fasting occasionally can dramatically improve body-fat composition and overall health.
Exercise scientist John Berardi says intermittent fasting is an effective way to melt body fat, boost the release of anti-aging hormones, and improve insulin sensitivity.
"Intermittent fasting reduces insulin levels, so you can actually increase your insulin sensitivity for better blood-sugar management," Berardi told Details. "At the same time, your body will release more growth hormone, which helps to preserve lean tissue and burn fat tissue."
Berardi says eating breakfast is optional, and slams the often-stated diet mantra that skipping meals slows metabolism. If anything, occasionally skipping meals and practicing intermittent fasting can improve metabolism by helping with blood-sugar management, appetite control, weight loss and increased cell repair.
"The idea that metabolism slows radically in response to not eating certain meals in a single day just isn't accurate," said Berardi, who has a Ph.D. in exercise physiology and nutrient biochemistry. "The amount of calories you're taking in and the composition of those calories — proteins, carbs, and fats — are really what impact metabolism."
For those who cringe even thinking about the word "fast," Berardi pointed out that most people already practice intermittent fasting, regardless of what diet they follow.
"No matter what eating style you follow, you already practice intermittent fasting," Berardi told T Nation. "If you typically eat dinner by 8 p.m. and breakfast at 8 a.m. the next day, you're fasting for 12 hours. Some refer to this as a 12/12 eating schedule because it's 12 hours of fasting and 12 hours of eating."
Intermittent fasting, or IF, does not mean starving oneself, and doesn't necessarily involve a reduction in total calorie intake. IF involves alternating periods of intentional fasting with intervals of (hopefully, healthy) eating. The eating pattern has recently been touted as a way to lose weight more quickly than conventional, linear dieting and is a cornerstone of many diets, including the Paleo diet.
Berardi, co-founder of Toronto-based Precision Nutrition, experienced dramatic results while experimenting with intermittent fasting. In 2011, Berardi tried several different IF formulas on himself over the span of six months and was able to shed 20 pounds of body fat while preserving most of his lean muscle mass (see before-and-after photos above).
During the process, Berardi chiseled his body from an already-impressive 10 percent body fat to a super-lean 4 percent.
Interestingly, he noted that intermittent fasting isn't just effective for weight loss, but can also accelerate muscle-mass gain for men who want to gain weight. However, it bears noting that IF is more effective for men than women and is not recommended for everyone.
While Berardi says intermittent fasting can dramatically improve most people's health, he underscored there's no one-size-fits-all formula. "The best one is the one that each individual dieter will stick with," he said.