Low-carbohydrate diets or low-carb diets are dietetic broadcasts that bound sugar intake commonly for weight hold or since the handling of fleshiness. Foods adenoidal in digestible sugars (for example. Breadstuff, pasta) are bounded or substituted on foods carrying an higher percentage of proteins and fats (e.g., meat, soy products) and often other foods low in carbohydrates (e.g., green leafy vegetables). The American Academy of Family Physicians provides the following definition of low-carbohydrate diets. Low-carbohydrate diets restrict caloric intake by reducing the consumption of carbohydrates to 20 to 60 g per day (typically less than 20 percent of the daily caloric intake). The consumption of protein and fat is increased to compensate for part of the calories that formerly came from carbohydrates. This definition is typical of most sources although no universally recognized definition has been established. Such diets are generally ketogenic (i.e. they restrict carbohydrate intake sufficiently to cause ketosis) for example, the induction phase of the Atkins diet. Some sources, though, consider less restrictive variants to be low-carbohydrate as well. Apart from obesity, low-carbohydrate diets are often discussed as treatments for some other conditions, most notably diabetesand epilepsy, although, other than for intractable epilepsy in children, these treatments still remain controversial and lack widespread support. Beginnings Some anthropologists believe that early humans were hunter-gatherers consuming diets high in both protein and fat and mostly low in nutritive carbohydrates (although their diets would have been high in fiber).[12][13] Indeed some isolated societies exist today which consume these types of diets. The advent of agriculture brought about the rise of civilization and the gradual rise of carbohydrate levels in human diets.[14] The modern age has seen a particularly steep rise in refined carbohydrate levels in Western societies. Practices and theories The term "low-carbohydrate diet" today is most strongly associated with the Atkins Diet. However, there is an array of other diets that share to varying degrees the same principles (e.g. theZone Diet, the Protein Power Lifeplan [ the Go Lower Diet and the South Beach Diet).] Therefore, there is no widely accepted definition of what precisely constitutes a low-carbohydrate diet. It is important to note that the level of carbohydrate consumption defined as low-carbohydrate by medical researchers may be different than the level of carbohydrate defined by diet advisors. For the purposes of this discussion, we focus on diets that reduce (nutritive) carbohydrate intake sufficiently to dramatically reduce insulin production in the body and to encourage ketosis (production of ketones to be used as energy in place of glucose). Scientific research Because of the substantial controversy regarding low-carbohydrate diets and even disagreements in interpreting the results of specific studies it is difficult to objectively summarize the research in a way that reflects scientific consensus. Although there has been some research done throughout the twentieth century, most directly relevant scientific studies have occurred in the 1990s and early 2000s and, as such, are relatively new. Researchers and other experts have published articles and studies that run the gamut from promoting the safety and efficacy of these dietsto questioning their long-term validity to outright condemning them as dangerous. Until recently a significant criticism of the diet trend was that there were no studies that evaluated the effects of the diets beyond a few months. However, studies are emerging which evaluate these diets over much longer periods, controlled studies as long as two years and survey studies as long as two decades. Major governmental and medical organizations Although opinions regarding low-carbohydrate diets vary greatly throughout the medical and nutritional science communities, major government bodies as well as major medical and nutritional associations have generally opposed this nutritional regimen. In recent years, however, some of these same organizations have gradually begun to relax their opposition to the point that some have even voiced cautious support for low-carbohydrate diets. The following are official statements from some of these organizations.