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Am J Clin Nutr. 2006 May;83(5):1055-61. Links
Comment in:
Am J Clin Nutr. 2007 Jan;85(1):238-9; author reply 239-40.
Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets.
* Johnston CS,
* Tjonn SL,
* Swan PD,
* White A,
* Hutchins H,
* Sears B.
Department of Nutrition, Arizona State University, Mesa, AZ 85212, USA. [email protected]
BACKGROUND: Low-carbohydrate diets may promote greater weight loss than does the conventional low-fat, high-carbohydrate diet. OBJECTIVE: We compared weight loss and biomarker change in adults adhering to a ketogenic low-carbohydrate (KLC) diet or a nonketogenic low-carbohydrate (NLC) diet. DESIGN: Twenty adults [body mass index (in kg/m(2)): 34.4 +/- 1.0] were randomly assigned to the KLC (60% of energy as fat, beginning with approximately 5% of energy as carbohydrate) or NLC (30% of energy as fat; approximately 40% of energy as carbohydrate) diet. During the 6-wk trial, participants were sedentary, and 24-h intakes were strictly controlled. RESULTS: Mean (+/-SE) weight losses (6.3 +/- 0.6 and 7.2 +/- 0.8 kg in KLC and NLC dieters, respectively; P = 0.324) and fat losses (3.4 and 5.5 kg in KLC and NLC dieters, respectively; P = 0.111) did not differ significantly by group after 6 wk. Blood beta-hydroxybutyrate in the KLC dieters was 3.6 times that in the NLC dieters at week 2 (P = 0.018), and LDL cholesterol was directly correlated with blood beta-hydroxybutyrate (r = 0.297, P = 0.025). Overall, insulin sensitivity and resting energy expenditure increased and serum gamma-glutamyltransferase concentrations decreased in both diet groups during the 6-wk trial (P < 0.05). However, inflammatory risk (arachidonic acid:eicosapentaenoic acid ratios in plasma phospholipids) and perceptions of vigor were more adversely affected by the KLC than by the NLC diet. CONCLUSIONS: KLC and NLC diets were equally effective in reducing body weight and insulin resistance, but the KLC diet was associated with several adverse metabolic and emotional effects. The use of ketogenic diets for weight loss is not warranted.
מה המשקל שלך
לכמה קיצצת ולאורך כמה זמן ללא העמסה
בעיקרון אתה יכול לבדוק בעצמך אם הגעת לקטוזיז בעזרת ketosticks או משהו מקביל שיש בבתי מרקחת
אתה סתם מבזבז אנרגיה.
RESULTS: Mean (+/-SE) weight losses (6.3 +/- 0.6 and 7.2 +/- 0.8 kg in KLC and NLC dieters, respectively; P = 0.324) and fat losses (3.4 and 5.5 kg in KLC and NLC dieters, respectively; P = 0.111) did not differ significantly by group after 6 wkאתה סתם מבזבז אנרגיה.
זה יעבור עוד שבוע בערך, אל דאגה
תדאג לשתות מספיק
This study certainly has a couple of strengths, controlled calorie levels (with food provision) and equal protein intake between groups being the two main ones. Weaknesses are the small sample size and the use of Tanita body fat measurement to track body composition. Changes in water balance can affect that method significantly and diets that manipulate carbohydrate content tend to impact significantly on water levels in the body.
With that said, this study adds to the data set suggesting that, if calories and protein intake are identical, there is little to no metabolic advantage (in terms of fat or weight loss) to full blown ketogenic diets. They work at least as well, mind you, but not better.
Now, as I discuss in the series of articles on Comparing the Diets, there still may be circumstances where very-low carbohydrate/ketogenic diets may still be preferred, even given the researchers comments above.
For many individuals, the biggest ‘metabolic advantage’ of very-low carbohdyrate diets may be one of food/calorie control. Many people seem to show what might be popularly called ‘carbohydrate addiction’ (a term that is massively debated among obesity researchers) where eating even small amounts of carbs makes them want to eat more. In that case, a full blown removal of carbohydrates from the diet may be the only realistic way to limit caloric intake.
Related to this, for many, spending time on a very-low carbohydrate diet seems to change taste preferences: carbohydrates can often be reintroduced after some period without the loss of food control that occurred prior to the diet.
I mentioned in the introduction that severely insulin resistant individual seem to get health benefits from extreme carbohydrate restriction. For leaner dieters, as I discuss in both The Ultimate Diet 2.0 and The Stubborn Fat Solution, extreme carbohydrate restriction tends to help with stubborn lower body fat mobilization.
But clearly in other situations, moderate carbohydrates diets (still containing sufficient protein mind you) may be superior. For people who can control their food intake, many simply feel better with more moderate carbohydrate intakes, their training (especially high intensity training such as weights) doesn’t suffer as much, and they don’t feel quite as lethargic. Again, these issues are discussed in detail in the Comparing the Diets series.
I guess my point is that there is too much variance between individuals and their needs to claim that any single diet is inherently superior for all people and all situations. As this study suggests, given identical calories and protein intake, there doesn’t seem to be any inherent metabolic advantage in terms of total fat loss to a full blown ketogenic diet, at least not when compared to a moderate carbohydrate diet with an identical amount of protein.
As I’ve noted above, there may be other ‘advantages’ unrelated to fat loss that are still important. Basically, the choice of diet may come down to other issues than fat loss per se. A diet that makes someone feel terrible isn’t one that they are likely to stick to for very long; a diet that does is one that may be the ’superior’ one for that person.
Finally, finally, if you want to hear more about my thoughts on this whole issue, Jimmy Moore of the Livin La Vida Lowcarb blog has just put up an audio interview we did a couple of months ago. We talk about everything related to low-carb diets you could imagine.
כדי שיהיה על מה לרשום ולמכור ספרים.RESULTS: Mean (+/-SE) weight losses (6.3 +/- 0.6 and 7.2 +/- 0.8 kg in KLC and NLC dieters, respectively; P = 0.324) and fat losses (3.4 and 5.5 kg in KLC and NLC dieters, respectively; P = 0.111) did not differ significantly by group after 6 wk
אני דובר אנגלית ברמה פחות או יותר זהה לעברית ואני מוכרח לציין שלא הצלחתי להבין מה רשום שם ב "תוצאות" (המבנה התחבירי לא מתחבר לי).
מישהו?
חחחחח עכשיו אחרי שהעתקתי את הקטע הרלוונטי כל המילים נפלו למקומן.
אז בעצם (לפי המחקר הספציפי הזה) אם בכלל יש עדיפות זה דווקא לדיאטת היותר שפויה מבחינת פחמימות. שלא לדבר על שאר הבעיות שמצוינות שם לגבי הקטו.
המממ...אז למה לדעתכם דיאטות אלו הפכו לכל כך פופולאריות?
כדי שיהיה על מה לרשום ולמכור ספרים.
לא, אתה מפרק יותר שומן (כביכול)רגע זה לא נכון ש:
כשנימצאים בקטוזיז מפרקים יותר שריר
וזה לא מצב שאתה רוצה להיות בו אלא רק להגיע אליו ואז לעשות העמסה