…the time frame from early dinner and late breakfast may range between 12-16 hours of fast, which is long enough to trigger natural adaptive ketosis and confers the same benefits of ketogenic diet. At the very least, food spacing anywhere from 4 to 8 hours has been shown to be beneficial for weight control and general health.


Introduction

Our ancestors started out as hunters and gatherers living on carbohydrates and meat. However, groups which were adept at hunting and fishing successfully migrated to the temperate and artic regions, where they lived for centuries in environments that did not support wild nuts or fruits. Before the influence of Europeans, the Intuit tribe of North American Artic lived on 99 per cent meat and preserved the glycogen content of their meat and therefore consumed more carbohydrates than thought. On the other hand, the Hadza and Bushmen of Africa represent two of the modern-day hunter-gatherer societies in the tropics. They would like to eat more meat, but year-round observation showed that they failed to kill wild game more than 50 per cent of the time and therefore lived on “gathering”, more than on “hunting”, with 70 per cent of their food being carbohydrates.

Therefore, the debates about high carbohydrates and high fat diets that have been going on since the middle of the twentieth century fail to recognise the reality that man has lived successfully on the available foods in his geographical locations. Studies have shown no evidence to recommend one diet over the other and chronic diseases such as obesity, diabetes, hypertension and heart diseases are rarely found among indigenous peoples who have not been influenced by civilisation, irrespective of the kinds of foods they consume.

No Love for Sugar and Body Fat

As the modern world engages in the privileged pastime of diets, mostly in the attempt to lose weight, sugar is fiercely hated but this flies in the face of the fact that everyone had their first sugar fix from their mama’s breastmilk in the form of lactose. Granted that sugar is not an essential nutrient, but its importance cannot be understated because the brain depends on glucose almost exclusively, except during periods of food scarcity or fasting. Just as sugar is hated, excessive body fat is nobody’s favourite either and this happens to be the main reason why most people want to lose weight but for a few Hollywood types who prefer cosmetic fat enhancements of their boobs and booties.

The truth remains that weight loss is quite easy but weight maintenance, which is another topic for another time, has always be the big issue. Besides, it is a little difficult to stay on ketogenic diet in Africa because carbohydrate is the staple food and protein/fat macronutrients are expensive.


Barring some medical issues, the truth is that everyone who stops eating would lose weight and those who go on diet or calorie restriction in whatever prevailing (diet) fads would lose weight until they fall off the wagon! Understandably, food is ubiquitous and its consumption is more than for keeping the body and soul alive, but represents a powerful social bonding on the family dinner table and for the celebration of milestones such as weddings, retirements, birthdays, funerals, send offs, sporting events, etc. Even occasional picnics where some form of exercises are performed often end up being occasions for outdoor grilling. No milestones invite comes with “bring your gym kits for all night exercise!” Never.

Back to sugar’s importance, glucose is a cheap form of energy and is often stored as glycogen in the liver and skeletal muscles. It is adaptively stored by the muscles for the next offence or defence in “flight or fight” situations or in modern times, to initiate vigorous physical activities, such as running or gardening. The liver on the other hand not only stores glycogen but can make glucose from the scratch when the stored glycogen is depleted during fasting or starvation, solely to keep the blood glucose in normal range and sustain the brain’s obligatory glucose need.

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Fasting, High Fat Diet and Ketosis

In normal condition, with a mix of carbohydrate and fat diet, some glucose is converted into a substrate called oxaloacetate which is needed for burning of the fat intermediate called acetyl coa in the Krebs cycle. This explains why it is often said that “fat burns in a carbohydrate flame.” During food scarcity, which was often during ancient times or during fasting in modern times, the body would release the stored fats which are then converted to acetyl coa by the liver. Because of the low level of glucose to fuel the Krebs cycle, this accumulating acetyl coa is again converted to ketone bodies in a process called ketosis. The brain then temporarily switches from glucose to keto metabolism until the next meal, because fat is unable to cross the blood brain barrier to reach the brain.

Should healthy individuals be concerned about skipping meals or fast now and then? Not in the least, literature shows that a lean adult stores enough fats or triglycerides worth 130,000 kilocalories. That is enough energy to run 50 marathons!


Keto metabolism is credited for improving our ancestor’s alertness and ability to keep going on empty stomach sometimes for days until they successful hunted the prey, gathered enough nuts/wild fruits or harvested honey. They only rested when they were full, otherwise they would never survive if they cowed to sitting while hungry! Ketosis is therefore based on intermittent fasting due to an unpredictable food supply. The ketogenic diet tries to mimic adaptive ketosis with the consumption of high fat and low carbohydrate in order to force the body into ketosis due to the presence of high fat intermediate and low glucose to burn the fat in the Krebs cycle. According to a 2014 review, there is a strong evidence that the ketogenic diet is effective in weight loss in the short term but not much data is available about long term effectiveness. I have read from and got invitations to join “ketogenic lifestyle” from my African friends on social media. The truth remains that weight loss is quite easy but weight maintenance, which is another topic for another time, has always be the big issue. Besides, it is a little difficult to stay on ketogenic diet in Africa because carbohydrate is the staple food and protein/fat macronutrients are expensive.

Conclusion

More importantly, dieting boils down to heeding grandma’s advice on food moderation, both in term of portion size and frequency. Studies have shown that there is no scientific basis for three meals plus snacks. For healthy individuals, the time frame from early dinner and late breakfast may range between 12-16 hours of fast, which is long enough to trigger natural adaptive ketosis and confers the same benefits of ketogenic diet. At the very least, food spacing anywhere from 4 to 8 hours has been shown to be beneficial for weight control and general health.

Should healthy individuals be concerned about skipping meals or fast now and then? Not in the least, literature shows that a lean adult stores enough fats or triglycerides worth 130,000 kilocalories. That is enough energy to run 50 marathons!

Mukaila Kareem, a doctor of physiotherapy, writes from the USA.