DIRECT Study result: Low-carb, Mediterranean diets win weight-loss battle

Drs. Iris Shai and colleagues released results of a new Israeli study, the Dietary Intervention Randomized Controlled Trial (DIRECT) Trial, that compared three different diet strategies. Of those tested, a low-carbohydrate diet was most successful at achieving weight loss.

You can find the full-text of the study on the New England Journal of Medicine website.

322 participants followed one of three diets over two year period. Compared head-to-head, the (mean) weight loss in each group was:

• 2.9 kg (6.4 lbs) for the low-fat group
• 4.4 kg (9.7 lbs) for the Mediterranean-diet group
• 4.7 kg (10.3 lbs) for the low-carbohydrate group

(Average age 52 years at start; average body-mass index, or BMI, 31.)

The conclusion was that the low-carb diet performed the best, with 60% greater weight loss, with the Mediterranean diet a close second.

The diets

The low-fat diet was based on the American Heart Association diet, with 30% of calories from fat (10% from saturated fat) and food choices weighted towards low-fat grains, vegetables, fruits, and legumes and limited additional fats, sweets, and high-fat snacks; calorie intake of 1500 kcal per day for women and 1800 kcal per day for men was encouraged.

The Mediterranean diet was a moderate-fat diet rich in vegetables, with reduced red meat, and poultry and fish replacing beef and lamb. Total calories from fat of 35% per day or less was the goal, with most fat calories from olive oil and a handful of nuts. Like the low-fat program, calories were limited to 1500 kcal per day for women, 1800 kcal per day for men.

The low-carbohydrate diet was patterned after the popular Atkins’ program, with 8% participants achieving the ketosis that Dr. Atkins’ advocated as evidence that a fat-burning metabolism was activated, rather than sugar-burning as fuel. For the 2-month “induction phase,” 20 grams of carbohydrates per day was set as the goal, followed by 120 grams per day once the weight goal was achieved. Unlike the other two diets, calories, protein and fat were unlimited.

Weight loss, lipids, inflammation

You can see from the weight loss graph that the low-carb approach exerted the most dramatic initial weight loss. Interestingly, much of the weight-loss benefit was lost as the carbohydrate intake increased, by study design, back to 120 mg per day. However, the other two diet approaches showed similar phenomena of “giving back” some of the initial weight loss.

The low-carbohydrate diet exerted the greatest change in cholesterol, or lipid, panels: increased HDL 8.4 mg/dl vs. 6.3 mg/dl on low-fat; the triglyceride response was the most dramatic, with a reduction of 23.7 mg/dl vs. 3.7 mg/dl on low-fat. Interestingly, the LDL cholesterol-reducing effect of all three diets was modest, with the most reduction achieved by the Mediteranean diet.

The inflammatory measure, C-reactive protein (CRP), was reduced most effectively by the low-carb and Mediterranean diets, least by the low-fat diet. HbA1c, a measure of long-term blood sugar, dropped significantly more on the low-carb diet.

When the final dietary composition was examined, interestingly, there really were only modest differences among the three diets, with 8% less calories from carbs, 8% greater calories from fat, comparing low-carb to low-fat, with Mediterranean intermediate.

Taken at face value, this useful exercise quite clearly shows that, from the perspective of weight loss and correction of metabolic parameters like triglycerides, HDL,CRP, and blood sugar, low-carbohydrate wins hands down, with Mediterranean diet a close second.

It also suggests that a return to a carbohydrate intake of 120 mg/day allows a partial return of initial weight lost, as well as deterioration of metabolic parameters after the initial positive changes.

Although the study has already received some criticism for such potential flaws as the modest number of Atkins’ followers achieving ketosis (8%), suggesting lax adherence, and the reintroduction of the 120 mg/day carbohydrate advice, I can suspect that these may have been compromises drawn to satisfy some Institutional Review Board. (Whenever a study is going to be conducted involving human subjects, a study needs to pass through the review of an Institutional Review Board, or IRB. IRB’s, while charged to protect human subjects from experimental abuses, also tend to be painfully conservative and will block a study or demand changes even if they are not dangerous, but just veer too far off the mainstream.)

However, several unanswered questions remain:

1) How would the diets have compared if the carbohydrate restriction were continued for a longer period, or even indefinitely? (The divergences would likely have been dramatic.)
2) Will low-carb exert the same cardiovascular event reduction that the Mediterranean approach has shown in the Lyon study and others?
3) Are there effects on health outside of the measures followed that differ among the three diets, such as cancer? (I doubt it, especially given the modest real differences over time. But this will be the objection raised by various "official" organizations.)

I would further propose that:

Low-fat diets are dead

The AHA will cling to their version of low-fat diet, based on difficulty in changing course for any large, consensus-driven organization, not to mention the substantial ($100’s of millions) revenues derived from endorsing low-fat manufactured products. The AHA will also point to the lack of difference in LDL cholesterol among the three, since they cannot get beyond the fact that there’s more to coronary risk—a lot more—than LDL.

Off-the-shelf diets achieve off-the-shelf results

If you just need a T-shirt, a medium might fit fine. But if you’d like a nicely fitting suit or dress, then tailoring to your individual proportions is needed. When aiming towards maximizing benefits on lipoproteins and coronary risk, none of these diets achieve the kinds of changes we often need for coronary plaque reversal, as in the Track Your Plaque program. That requires making dietary changes that exert maximal effects on lipoprotein patterns.

Comments (14) -

  • Jenny

    7/19/2008 3:30:00 PM |

    Dr. Eades also has an interesting take on this study on his blog.
    Many comments responding to it are interesting and worth reading as well, (Dr. Eades appears to have many readers with the same ability to cut through BS as those of the HeartScanBlog )  but two that I found especially revealing deal with how this study was reported by the press outside the US.  According to one commenter, in the UK the Daily Telegraph headline said, "Low-fat diets 'not as effective for weight loss'", and the Daily Mail's, "the controversial Atkins Diet is 'safe and far more effective than a low-fat one',study shows".   Another commenter said that in the Philippines, the Philippine Inquirer said "Low-carb diet proven best for weight control." In this country even the way an "objective" report on this subject is titled in the press seems colored by  distaste (fear?) and reluctance to give the facts their due.

  • Juhana Harju

    7/19/2008 4:52:00 PM |

    You have an interesting blog that I have been following for some time already. Personally I am a proponent of Mediterranean diet, but I would like to say that I do not agree with your claim that low fat diets are dead.

    It should be noticed that the DIRECT study was a weight loss diet for people who were obese (average BMI 31). It is well known that low fat diets are not ideal for people who are overweight or people with insulin resistance. However, low fat diets can be quite suitable for lean and active people. Japan is a good example of a population where the diet is still low fat and its coronary heart disease risk is low.

  • Aaron

    7/20/2008 7:22:00 PM |

    This study didn't prove much.  Look at the weight gain that occurred after 1 year on the diet (2 year study).  When is there going to be a true study done on a nutrient dense low fat diet (not 30% of calories like was done in this study) vs a paleo type diet and a not a vegetarian atkins-esc diet.  This study just adds to confusion.

  • Anonymous

    7/20/2008 10:11:00 PM |

    Japan may have lower heart attacks but they are suffering from thyroid problems from so called health food "soy".

  • Juhana Harju

    7/21/2008 5:04:00 AM |

    Anonymous wrote:

    "Japan may have lower heart attacks but they are suffering from thyroid problems from so called health food 'soy'."

    Soy has some harmful effects but I think that the benefial effects of soy outweigh them. Japan has one of the highest life-expectancies and the highest healthy life-expectancy in the world. For me this shows that much of what they are doing is probably right inspite of their stressful working life.

    PS. The blog takes very long to download, probably due to the Digg application and many other features.

  • Jeff Consiglio

    7/22/2008 12:55:00 PM |

    I found it interesting that certain biomarkers became less favorable within the low carb group, when they upped carbs to a mere 120 grams per day. That sure is motivation to watch one's intake of carbs! BTW, I love your take on the AHA. Cocoa Puffs are "heart friendly" just because they are low in fat? Pleeeease!

  • George

    7/22/2008 8:49:00 PM |

    I wonder if Dr. Davis could comment or rebut Dr. Ornish's expected rebuttal to this study in the latest newsweek issue. Here is the link

    Great blog, great information

  • Stephen

    7/22/2008 11:58:00 PM |

    Gee, if they are making that much from endorsements, disclaimers are appropriate every time they push a diet that connects to an endorsement.

    was great too.

    However, most people who are concerned with diet are those who are overweight.

    Juhana, yes, when I had time to exercise 20+ hours a week, an entirely different pattern of eating was appropriate than when I had a job and many fewer hours.

    I don't see the point.  Few of us are currently competitive athletes right now.

  • Juhana Harju

    7/23/2008 5:33:00 AM |

    Stephen, Japanese are doing fine without 20 hours of exercise a week.

    In my opinion, reducing carbs is necessary only when you already have an abnormal glucose metabolism due to overeating, high intake of refined carbs and sedentary lifestyle. High prevalance of overweight, obese and diabetic people is clearly a modern phenomenon.

  • renegadediabetic

    7/23/2008 2:11:00 PM |

    I too am not sure that low fat is dead.  I still hear a lot of low fat nonsense everywhere I turn.

    Low fat should be dead, but there are too many folks in the medical-dietary establishement who want to keep it on life support.

  • Anonymous

    2/2/2010 12:52:35 AM |

    My friend and I were recently talking about the prevalence of technology in our day to day lives. Reading this post makes me think back to that discussion we had, and just how inseparable from electronics we have all become.

    I don't mean this in a bad way, of course! Ethical concerns aside... I just hope that as the price of memory falls, the possibility of transferring our brains onto a digital medium becomes a true reality. It's one of the things I really wish I could experience in my lifetime.

    (Posted on Nintendo DS running [url=]R4 SDHC[/url] DS FPost)

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  • buy jeans

    11/3/2010 6:45:35 PM |

    The Mediterranean diet was a moderate-fat diet rich in vegetables, with reduced red meat, and poultry and fish replacing beef and lamb. Total calories from fat of 35% per day or less was the goal, with most fat calories from olive oil and a handful of nuts. Like the low-fat program, calories were limited to 1500 kcal per day for women, 1800 kcal per day for men.

  • farseas

    7/11/2011 8:32:53 PM |

    Could you please quote sources that show that the Japanese have a thyroid problem induced by soy.  I think that soy bashing is a bunch of hype.

Why obese people can't fast

Why obese people can't fast

Why do obese people claim it is impossible to fast?

Most overweight people are terrified at the prospect of facing any period of time without ready access to food. Persuading them to begin a program of intermittent fasting is a hopeless cause. They just refuse.

Contrary to popular opinion, this is not just glutonny at work. It is the effect of what I call "the cycle of hunger," the 2-hour up and down cycle of rising sugar and insulin, followed by their inevitable fall. The precipitous fall of sugar and insulin triggers mental fogginess, fatigue, and insatiable hunger. (By the way, this is the same phenomenon underlying the silly notion of "grazing.")

According to an LA Times article, fasting may be difficult to impossible for some people:

"Ruth Frechman, a registered dietitian in Burbank and spokeswoman for the American Dietetic Assn., says she frequently sees such extreme strategies backfire. 'You're hungry, fatigued, irritable. Fasting is not very comfortable. People try to cut back one day and the next day they're starving and they overeat.'"
(Not surprising, coming from the American Diatetic Assn. They, along with such agencies as the American Diabetes Association, are vocal proponents of low-fat, high-carbohydrate, "healthy whole grain" diets--you know, the diets that make us fat and diabetic.)

Ms. Frechman is correct: Having someone engage in a period of fasting, no matter how brief, when the diet leading up to the fast is filled with "healthy whole grains" and other carbohydrates will result in painful hunger that eventually overcomes any effort. A period of overeating typically follows the aborted attempt.

Fasting cannot work as long as the 2-hour cycle of hunger continues. The first step: Eliminate the 2-hour cycle of hunger by dramatically reducing or eliminating carbohydrates. Our preferred method is to eliminate wheat, cornstarch, and sugars. (Just be aware of wheat withdrawal, the fatigue that develops in the first 5 days after wheat elimination that affects up to 30% of people.)

Once wheat, cornstarch, and sugars are eliminated, hunger reverts to that of physiologic need--appetite will be smaller and less intense, since it is driven by your body's needs, not by abnormal stimulation from wheat, cornstarch, and sugar. The fear of not having food dissolves, the 2-hour cycle of mental fogginess, fatigue, and hunger will be gone.

Intermittent fasting is a wonderful strategy for reducing weight; gaining control over lipids, lipoproteins, and coronary plaque; regaining appreciation for food; reducing appetite. But it's not even worth trying unless you've already eliminated the unnatural appetite triggers that will booby-trap any fasting effort.

Comments (21) -

  • Anonymous

    9/9/2009 12:21:40 AM |

    I agree with your post.
    Once you are adapted to a low carb diet Intermittant Fasting becomes really easy and you feel great without becoming hungry or mentally foggy. I wouldn't dream of trying IF on a high carb diet since it would be like self torture.


  • rfrancis

    9/9/2009 12:47:06 AM |

    Dr. Davis,

    I agree with you as far as this goes -- but I'd go a bit further.

    For those (myself included) who are substantially insulin resistant, and in particular type II diabetic, even years of a low carb diet may not beat the hunger cycle, very possibly (c.f. Gary Taubes and others) because that very insulin resistance interferes with the release of stored energy, ensuring that the insulin resistant person becomes hungry again every time they've exhausted (or worse, stored!) the energy obtained from their last meal.  Feelings of muscular tiredness, lethargy, even mysterious panic -- I doubt anyone chronically obese is strangers to some or all of these.

    Of course, even so, the first step is exactly as you say.  As for what comes next... I'm all ears. Smile  Personally, I'm trying to get my physician to at least investigate possible connections between subclinical hypothyroid and insulin resistance...

  • Stan (Heretic)

    9/9/2009 1:36:01 AM |

    Anonymous wrote: "Once you are adapted to a low carb diet Intermittent Fasting becomes really easy and you feel great without becoming hungry or mentally foggy."

    Absolutely!  On a high (animal) fat diet, our metabolism is identical to a fasting metabolism, therefore there is no noticeable change in feeling, stamina, not much hunger even after a couple of days!  There isn't much need to drink water either, since fat burning produces water.   Also we typically eat only one meal a day - that is completely sufficient without any need to snack.


  • Ross

    9/9/2009 3:07:45 AM |

    Very similar to my own experience.  I used to try fasting, as my very liberal friends used to tell me that it's great for "purification" and "detoxification", but I couldn't hack it.

    Now I do a 36 hour "after dinner to before breakfast" fast about once a week (on random days of the week to shake things up) and the strongest symptom I have is during the afternoon and evening of the fasting day I get very mellow and relaxed.  I also feel small hunger pangs as I go to bed and that's about it.

  • Andrew

    9/9/2009 3:13:16 AM |

    gft chromium helps with fat metabolism

  • Rick

    9/9/2009 5:37:00 AM |

    Dr. Davis,
    Could you expand a bit on what you mean by the 2-hour cycle?

  • Lincoln

    9/9/2009 7:55:10 AM |

    This is a really good article which clearly explains the concept of the hunger cycle.  From my experience if people are particularly insulin resistance then a longer lead in time of gradually reducing carbs helps the body to adjust.  Then it is possible to include a period of fasting.



  • Daddy

    9/9/2009 9:23:47 AM |

    I have only recently started in with the low carb diet.  I was curious if there is any knock against dairy too.  Thanks!

  • Methuselah

    9/9/2009 11:49:19 AM |

    Your article makes perfect sense, but the title is a little misleading. Clearly once an obese person has removed the 'unnatural appetite triggers' they will be able to fast as comfortably as a slender person who has eliminated those triggers. Indeed an obese person who has emiminated the triggers might be more able to fast than a slender person who has not.

  • Dr. William Davis

    9/9/2009 12:11:18 PM |

    Hi, Rick--

    After a carbohydrate load, blood sugar (glucose) increases sharply, followed by insulin. In response to insulin, blood sugar drops precipitously, often to levels below normal. This is where all the symptoms like mental fogginess develop.

    The entire cycle requires 90-120 minutes or so, depending on the foods consumed, the mix of foods and food types consumed, and individual responsiveness.

    Interestingly, of all foods, wheat triggers the fastest and highest glucose peaks, even compared to table sugar (sucrose).

  • Susan

    9/9/2009 1:03:31 PM |

    One thing you find when you go wheat-free (let alone low carb) is how difficult it is to buy anything for lunch that isn't wheat based. The great thing about IF is that it frees you from the endless repetition of "chicken caesar salad, please, hold the croutons and bacon bits." (Bacon bits are out because they're usually fake.) In fact, after a couple of days, you  can walk through a food court, and your only reaction is to marvel that all of these people are eating lunch, which is totally unnecessary. The other thing about IF is that it also makes it easier to say no to snacking or other mindless eating.

  • Anonymous

    9/9/2009 1:57:38 PM |

    I just want to know how all of you take your vitamins and other pills on an empty stomach?  I would vomit them right back up!

  • Gretchen

    9/9/2009 3:17:38 PM |

    It's not just "mental fogginess, fatigue, and insatiable hunger" that is the problem. When I was prediabetic and trying to lose weight, I had difficulty going on a diet because when I cut back on my food intake, I'd get what I now know are symptoms of hypoglycemia.

    I actually enjoyed being hungry, because it told me I was eating less than I needed.

    What I couldn't tolerate was "the shakes," accompanied by a feeling of panic that if I didn't eat immediately I'd die.

    Because many overweight people are also prediabetic, they probably have the same symptoms of hypoglycemia, caused by "too much insulin, too late."


    9/11/2009 11:20:13 PM |

    As a former Fatty, I can understand the difficulties some would have with Intermittent fasting. Two points:  don’t start here. I managed to control my carb carvings first with Atkins, then was able to move on to Intermittent fasting when I was ready.
    Second- I don’t like that Ruth Frechman calls IF an “extreme strategy”- it just might be the healthiest Life Saver going.

  • Dr. William Davis

    9/12/2009 12:28:48 AM |


    I agree wholeheartedly.

    It shows how far our diets have drifted from the physiologic ideal when we have to shift away from it in steps!

  • PJ

    9/22/2009 2:41:42 PM |

    Um. I weigh about 380 and I have no trouble fasting. In fact it's 9:39am here on a Tuesday and the last time I ate was Sunday around 9pm. This is not because I was doing it on purpose (though I could retroactively assign some glorious reason to it I suppose), but because I'm painting my kitchen so making food was a pain in the butt and I didn't feel like it.

    However when I'm eating highcarb, going without food is horribly hard. The fact that I eat lowcarb is probably what makes it possible for me.

  • Matt Metzgar

    9/27/2009 6:19:05 PM |

    I agree completely with this.  If a person hasn't made the metabolic shift to fat-burning, then fasting will be painful.

  • trinkwasser

    10/2/2009 3:31:09 PM |

    Another "me too": my pattern was high BG at around 1 hour postprandial, returning to normal at two hours and dipping significantly below normal at three or more hours.

    This improved markedly with carb reduction, but I still needed to snack, until I started replacing those "heart healthy" Omega 6s with saturated fat.

    Getting the correct macronutrient balance *for me* lets me routinely go about six hours between eating, whatever my activity level, and those 14 hour fasts for blood tests don't have the response they used to cause.

    I'm still somewhat leery of fasting for that much longer though, as the resulting hypo symptoms and ensuing BG swings as my liver overcompensates are Not Nice and I don't want to push things so far that I restart this phenomenon

  • buy jeans

    11/3/2010 8:26:17 PM |

    Intermittent fasting is a wonderful strategy for reducing weight; gaining control over lipids, lipoproteins, and coronary plaque; regaining appreciation for food; reducing appetite. But it's not even worth trying unless you've already eliminated the unnatural appetite triggers that will booby-trap any fasting effort.

  • Jessica

    3/7/2012 6:56:48 PM |

    I''m fat.  I''m 245 lbs which is considered small on the morbidly obese scale, but still morbidly obese.  I have fasted a day at a time, every other day in prep for my 7 day trial.  I am starting my 7 day today.  Hopefully I don''t s**t the bed on this one.  I''m tired of being a fat ass, literally.

  • Gene K

    3/8/2012 7:20:10 PM |

    You may find the blog of Dr Jack Kruse useful, especially this post - Definitely read all comments, and try to read as many of his other leptin-related posts as possible.