It's not chock full of hard scientific evidence, and I think I have heard this idea before concerning the food + tired feeling, but nonetheless interesting.

Via HumanNatura.org

Feast-Fast Eating For Superior Health

A Switch to One Large Evening Meal Each Day May Offer Significant Health Improvements


Greg Battaglia © 2006

Being a part of the HumanaNatura community, we all aspire to achieve optimal levels of health and vitality through the use of evolutionary health practices. The foods that we eat are composed of the raw materials that humans are designed by nature to eat, the exercises we engage in mimic the activity patterns of our ancestors, and we strive to obtain and maintain healthy sexual and social lifestyles. The area that I want to focus on in this article is the topic of nutrition and diet, but more importantly on meal frequency.

When viewing meal frequency through an evolutionary scope, one can easily conclude that humans certainly did not evolve to consume food very frequently. In nature there is no absolute guarantee that food will be available or when it will be available. It is likely that humans would have been subjected to many hours or even days without food throughout the entirety of our evolution. It is also likely that when food did become available, for example, after a vigorous but successful hunt, that our ancestors would have consumed a large quantity of calories to make up for the deficit created during the fast. Once a kill and any gatherings were completely eaten, the fast would then begin once again and this cycle might continue as the basic template for a typical hunter-gatherer (H/G) eating pattern.

This same logic is consistent with the fact that many humans find it difficult to exercise on a full stomach. The question that must be asked in order to find the solution to this problem is: Why would H/G’s pursue food? The answer to this question is obviously because they were hungry! It only makes sense that H/G’s would exercise (hunt and gather) on an empty stomach because hunger is what initially motivated them to seek out food in the first place. It is therefore reasonable to assume that the human body will perform better both mentally and physically in a fasted state, due to the heavy reliance on this ability during the Paleolithic era of human evolution. During a hunt, humans would be required to be physically light and agile and mentally sharp in order to be successful. People who could not do this did not survive and ultimately failed to pass their genes on to the next generation.

The fact that people are more adapted to a feast-fast feeding cycle also may help to explain why modern humans have such a tendency to be sedentary. Since the advent of agriculture, the availability of food has become more constant. Rather than periodically hunting or gathering food, people now simply need to hop in their car, drive to the nearest grocery store, and are immediately supplied with a plethora of easily accessible, high calorie foodstuffs. The fact that modern people eat whenever they please removes feelings of urgency for hunting and gathering (exercise and other activity) and greatly influences our sedentary lifestyle. It is my contention that if modern people were to adopt a more evolutionarily appropriate meal frequency, they would also regain the desire to be active, resulting in a simultaneous improvement in both diet and exercise patterns.

So the central question is: How often should I eat in order to mimic the meal frequency that I would be presented with in nature? The answer to this question needs to be expressed as a range, since there was likely fairly high variation in food availability in different regions of the world and at different times of the year during our ancient life in nature. For instance, H/G’s living in Central Africa would normally have a much larger variety of plant food sources that could be consumed between hunts, reducing the fasting period. However, H/G’s living in Alaska would be much more dependent on animal sources for most, if not all, of his calories, which would result in longer fasting periods due to the inability to snack on plant foods between catches.

Loren Cordain, a leading researcher in Paleolithic nutrition, has concluded from studies done on modern day H/G’s, that the natural meal frequency for humans is characterized by one large feeding a day, which is consumed at night. This follows logic, as it would make sense that H/G’s would hunt during the day and then eat one large meal after a successful hunt. This eating pattern is probably conducive to proper sleeping patterns too. Meals tend to raise and then lower blood sugar levels and cause one to feel tired and lethargic, which is often seen in individuals who eat three large meals a day. The fact that meals tend cause one to feel tired is evidence enough to suggest that eating large meals during the day will greatly increase the likelihood one will avoid exercise due to lethargy. It is also supportive of the single large nighttime feeding, as a feeling of tiredness and exhaustion is appropriate to prepare one for sleep.

It is also important to note that a feast-fast eating pattern has been indicated in the scientific literature to decrease the occurrence of Syndrome X diseases (heart disease, diabetes, hypertension, stroke, etc) and increase life span in laboratory animals. What these studies have found is that by putting mice on a day-on/day-off feeding cycle, researches were able to increase their life span by as much or more than mice on a calorie-restricted diet (which has already been shown to be life-extending versus higher-calorie diets). The studies also observed a reduction in blood sugar levels, insulin levels, and improvements in blood lipid profiles, suggesting that intermittent fasting may be an effective tool in the prevention and treatment of diseases of modern civilization. Studies are currently in progress on squirrel monkeys, close biological cousins to humans, and have so far found similar beneficial health effects of intermittent fasting. Other studies utilizing intermittent fasting have yielded improvements in markers for disease.

With compelling ideas and evidence coming from evolutionary theory, observation of H/G populations, and scientific studies, it would be wise to consider a feast-fast meal frequency as part of the HumanaNatura lifestyle and reduce the frequency of large meals. The evidence seems to suggest that one large nighttime meal per day is appropriate for the human biological design, with fasting or light meals in between. The effects of this pattern of eating is still being studied, but may offer significant health benefits and a more active lifestyle.


Greg Battaglia is a member of the HumanaNatura community

Sources:

Beneficial effects of intermittent fasting and caloric restriction on the cardiovascular and cerebrovascular systems.

Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake.

Posted By Greg Battaglia, December 12th, 2006