3. Myth: Eat small meals to keep blood sugar levels under control.
Truth
According to legions of diet and health "experts," eating small meals every so often will help you avoid hunger pangs, provide you with stable energy throughout the day and keep you mentally sharp. Contrary to what many people seem to believe, blood sugar is extremely well-regulated and maintained within a tight range in healthy people. It does not swing wildly up and down like a chimpanzee on meth and it doesn't plummet from going a few hours without food. Or even a full day without food. Or a week without food for that matter.
People seem to believe they will suffer severe hunger and mental impairment from not eating every so often. Consider for a second the evolutionary consequences for survival if this was true. Given that regular periods of fasting, even famine, was a natural part of our past, do you think we'd be here today if we were unable to function when obtaining food was most critical? I have seen healthy young males, bodybuilders nonetheless, complain of lethargy and mental haze if they didn't get to eat for a few hours. It's completely absurd. But I digress...
Maintaining blood sugar is of very high priority and we have developed efficient pathways that will make it happen even under extreme conditions. If you were to fast for 23 hrs and then go for a 90 min run at 70-75% VO2max, your blood sugar after the run would be identical to the same run performed in the fed state. It would take no less than three days or 84 hours of fasting to reach blood sugar levels low enough to affect your mental state; and this is temporary, as your brain adapts to the use of ketones. During 48 hours of fasting, or severe calorie deprivation, blood sugar is maintained within a normal range no measure of cognitive performance is negatively affected.
For more on blood sugar, read my review of Eat Stop Eat Expanded Edition, which includes a relevant excerpt. Also, keep in mind that the above cited studies are all performed under conditions that are much more extreme than the fasting protocol I, or Brad Pilon, recommends.
What about blood sugar and hunger? Blood sugar is one of many short-term feedback mechanisms used to regulate hunger and the notion which exists to say that low blood sugar may cause hunger is correct. Low just means lower range. This is subject to numerous confounders, such as your habitual diet, energy intake and genetics. Most importantly perhaps, it's subject to entrained meal patterns, regulated by ghrelin and other metabolic hormones. In essence, this means that blood sugar follows the meal pattern you are used to. This is relevant for those who fear blood sugar issues and hunger from regular periods of fasting, as it serves to explain why people can easily adapt to regular periods of fasting without negative effects.
Origin
Not sure how people came to believe that skipping a meal would dumb them down. There is some truth to blood sugar and hunger, but this is often taken out of context. There's no need to eat regularly to "maintain" blood sugar as it maintains itself just fine and adapts to whatever meal pattern you choose.
