They have the same effect on the body! Some waffle from good old wikipedia:
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. the
Zone Diet, the Protein Power Lifeplan,[SUP]
[43][/SUP] The Primal Blueprint,[SUP]
[44][/SUP] the Go Lower Diet,[SUP]
[45][/SUP]
The Earth Diet and the
South Beach Diet).[SUP]
[46][/SUP] The
American Academy of Family Physicians defines low-carbohydrate diets as diets that restrict carbohydrate intake to 20g to 60g per day.[SUP]
[47][/SUP] Atkins (in the later phases) and some other low-carbohydrate diets exceed the 60g limit definition by this group. 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 from the level of carbohydrate defined by diet advisors. For the purposes of this discussion, this article focuses 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).
Although low-carbohydrate diets were originally created on the basis of anecdotal evidence of their effectiveness, today there is a much greater theoretical basis on which these diets rest.[SUP]
[48][/SUP][SUP]
[49][/SUP] The key scientific principle which forms the basis for these diets is the relationship between consumption of carbohydrates and the subsequent effect on
blood sugar (i.e. blood
glucose) and on production of certain specific
hormones. Blood sugar levels in the human body must be maintained in a fairly narrow range to maintain health. The two primary hormones related to regulating blood sugar levels, produced in the
pancreas, are insulin, which lowers blood sugar levels (among many other effects, most of considerable metabolic significance), and
glucagon, which raises blood sugar levels.[SUP]
[50][/SUP] In general, most
western diets (and many others) are sufficiently high in nutritive carbohydrates that nearly all meals evoke insulin secretion from the
beta cells in the pancreas; carbohydrates which are digested to produce glucose in the blood stream are the primary control for insulin secretion. Another aspect of insulin secretion is control of
ketosis; in the non-ketotic state, the human body stores dietary fat in fat cells (i.e., adipose tissue) and preferentially uses glucose as cellular fuel. By contrast, low-carbohydrate diets, or more properly, diets that are very low in nutritive carbohydrates, evoke less insulin (to cover the ingested glucose in the blood stream), leading to longer and more frequent episodes of ketosis. Some researchers suggest that this causes body fat to be eliminated from the body, although this theory remains controversial, insofar as it refers to excretion of lipids (i.e., fat and oil) and not to fat metabolism during ketosis.[SUP]
[51][/SUP]
Low-carbohydrate diet advocates in general recommend reducing nutritive carbohydrates (commonly referred to as "net carbs," i.e. grams of total carbohydrates reduced by the non-nutritive carbohydrates)[SUP]
[52][/SUP][SUP]
[53][/SUP] to very low levels. This means sharply reducing consumption of desserts, breads, pastas, potatoes, rice, and other sweet or starchy foods. Some recommend levels less than 20 grams of "net carbs" per day, at least in the early stages of dieting[SUP]
[54][/SUP] (for comparison, a single slice of white bread typically contains 15 grams of carbohydrate, almost entirely starch). By contrast, the
U.S. Institute of Medicine recommends a minimum intake of 130 grams of carbohydrate per day (the
FAO and
WHO similarly recommend that the majority of dietary energy come from carbohydrates).[SUP]
[55][/SUP][SUP]
[56][/SUP]
Low-carbohydrate diets often differ in the specific amount of carbohydrate intake allowed, whether certain types of foods are preferred, whether occasional exceptions are allowed, etc. Generally they all agree that processed sugar should be eliminated, or at the very least greatly reduced, and similarly generally discourage heavily processed grains (white bread, etc.). Low-carbohydrate diets vary greatly in their recommendations as to the amount of fat allowed in the diet. The
Atkins Diet does not limit fat. Others recommend a moderate fat intake.
Although low-carbohydrate diets are most commonly discussed as a weight-loss approach, some experts have proposed using low-carbohydrate diets to mitigate or prevent diseases including diabetes, metabolic disease and epilepsy.[SUP]
[57][/SUP][SUP]
[58][/SUP] Some low-carbohydrate proponents and others argue that the rise in carbohydrate consumption, especially refined carbohydrates, caused the epidemic levels of many diseases in modern society, including metabolic disease and type 2 diabetes.[SUP]
[59][/SUP][SUP]
[60][/SUP][SUP]
[61][/SUP][SUP][
unreliable source?][/SUP]
There is also a category of diets known as
low-glycemic-index diets (low-GI diets) or low-glycemic-load diets (low-GL diets), in particular the Low GI Diet by Brand-Miller et al.[SUP]
[62][/SUP] In reality, low-carbohydrate diets can also be low-GL diets (and vice versa) depending on the carbohydrates in a particular diet. In practice, though, "low-GI"/"low-GL" diets differ from "low-carb" diets in the following ways. First, low-carbohydrate diets treat all nutritive carbohydrates as having the same effect on metabolism, and generally assume that their effect is predictable. Low-GI/low-GL diets are based on the measured change in blood glucose levels in various carbohydrates - these vary markedly in laboratory studies. The differences are due to poorly understood digestive differences between foods. However, as foods influence digestion in complex ways (e.g., both protein and fat delay absorption of glucose from carbohydrates eaten at the same time) it is difficult to even approximate the glycemic effect (e.g., over time or even in total in some cases) of a particular meal.
Another related diet type, the
low-insulin-index diet, is similar except that it is based on measurements of direct insulemic responses (i.e., the amount of
insulin in the bloodstream) to food rather than glycemic response (the amount of
glucose in the bloodstream). Although such diet recommendations mostly involve lowering nutritive carbohydrates, there are some low-carbohydrate foods that are discouraged as well (e.g., beef).[SUP]
[63][/SUP] Insulin secretion is stimulated (though less strongly) by other dietary intake. Like glycemic index diets, there is difficulty predicting the insulin secretion from any particular meal, due to assorted digestive interactions and so differing effects on insulin release.
[h=2][
edit][/h]