Arguments in favor of ketogenic diets - Nutrition and Metabolism ...

More documents

Recommendations

Info

http://www.ispub.com/journal/the_internet_journal_of_nutrition_and_wellness/volume_4_number...Page 2 of 435/28/2011way of losing weight. It is also argued that such diets provide metabolicadvantages, for example: they help to preserve muscle mass, reduceappetite, diminish metabolic efficiency, induce metabolic activation ofthermogenesis and favor increased fat loss and even a greater reduction incalories. These diets are also healthier because they promote a nonatherogeniclipid profile, lower blood pressure and decrease resistance toinsulin with an improvement in blood levels of glucose and insulin. Lowcarbohydratediets should therefore be used to prevent and treat type IIdiabetes and cardiovascular problems. Such diets also have neurologicaland antineoplastic benefits and diet-induced ketosis is not associated withmetabolic acidosis, nor do such diets alter kidney, liver or heart functions.The Evolution Of The HumanDietHumanity has existed as a genus for about 2 million years, and ourprehuman hominid ancestors, the australopithecines, appeared at least 4million years ago. This phase of evolutionary history made definitivecontributions to our current genetic composition, partly in response todietary influences at that time. The development of agriculture 10000 yearsago has apparently had a minimal influence on our genes and markedlyaltered human nutritional patterns. In the hunting society of our ancestorsprotein contributed twice to nearly five times the proportion of totalcalories that it does for nowadays Americans 1 .Since then, the human diet has changed drastically: protein intake has beenreduced to 10-15%; glucid intake has increased to 45-60% through eatingmore grain and starch products instead of vegetables and fruits availableaccording to the seasonal conditions; polyunsaturated fat has been reducedand saturated fat has increased (lower polyunsaturated-to-saturated fatradio) 1 . So we can affirm that healthier fats like monounsaturated andpolyunsaturated fats (MUFA and PUFA) have been replaced by morepernicious fat like saturated and, above all, the artificial trans fats.
http://www.ispub.com/journal/the_internet_journal_of_nutrition_and_wellness/volume_4_number...Page 3 of 435/28/2011Furthermore, carbohydrates consumed nowadays tend to have a higherglycemic index and glycemic load since they are based on grains, starch andrefined sugars instead of vegetables and fruits. In such a short evolutionaryperiod of time, human beings have been unable to adapt to this abruptchange in eating habits, and this has been a significant source of stress forour insulin metabolism.The fact that the nutritional change from a hunter-gatherer diet to acarbohydrate-based diet has affected populations negatively has beenrevealed by archaeological findings in ancient Egyptian mummies, sincetooth decay, cardiovascular disease and obesity were very frequent in thosetimes 8 . More recently, this problem has also been reflected historically bythe change in eating habits of Inuit peoples in Alaska. Traditionally, theirdiet contained 3-5% carbohydrates (since it was based on fish, marinemammals, moose and caribou), obesity was virtually nonexistent and typeII diabetes was rare. Since 1961, a growing tendency in type II diabetes andobesity problems has been observed due to a progressive substitution of thetraditional protein and fat-based diet by a diet with higher carbohydratecontent. This increase has been so dramatic that in 1978, carbohydratesrepresented 50% of the total calorie contribution in their diet 9 . Anotherhistorical fact worth considering when analyzing the nutritional habits ofAmerican society is their increased consumption of carbohydrates, eitherthrough eating more food in general or by replacing fats withcarbohydrates. This leads to an increase in obesity and atherogenic markerssuch as triglycerides and VLDL 10] .Most hunter–gatherers, for example, are not obese when they live theirtraditional lifestyle based on a low carbohydrate diet. Many huntergatherersconsumed a predominantly plant-based diet, which wassupplemented with meat when available, and others such as the Inuitsconsumed a high fat-protein diet. When such people are exposed to high,refined carbohydrate intake, however, they develop truncal obesity and amuch higher risk of diabetes, up to 50% in some populations. This highwaist-hip ratio and carbohydrate intolerance is shared by all hunter–
Page 1: http://www.ispub.com/journal/the_in
Page 5 and 6: http://www.ispub.com/journal/the_in

Arguments in favor of ketogenic diets - Nutrition and Metabolism ...

Create successful ePaper yourself

Delete template?

Save as template?