Evidence for the Paleo Diet and Weight Loss?

Early in 2013, US News & World Report asked a panel of 22 diet experts to rank 28 popular diets. The criteria: Were they effective for short-term or long-term weight reduction? Were they easy to follow? Were they safe and nutritionally balanced?

Topping the list was the DASH diet. (A variation of DASH called OmniHeart is the diet recommended by most health experts.)


Dead last? The Paleo diet, which the panel noted was supported by studies that were “few, small, and short.”

Loren Cordain, an exercise physiologist at Colorado State University and author of The Paleo Answer: 7 Days to Lose Weight, Feel Great, Stay Young, disputed the panel’s conclusions.

“Five studies, including four since 2007, have tested ancestral—or Paleo—diets and have found them superior to Mediterranean diets, diabetic diets and typical Western diets in regards to weight loss, cardiovascular disease risk factors, and risk factors for type 2 diabetes,” he wrote to the magazine.

But all five studies cited by Cordain were just as US News said: small and short term. Three of the five didn’t compare people who were randomly assigned to either the Paleo diet or another diet. Without that “control group” following another diet, researchers couldn’t tell if people lost weight because they were on a particular diet or simply because they were participating in a study.

In one of the two studies that did compare Paleo with other diets, Swedish researchers randomly assigned 29 middle-aged or older men with heart disease and pre-diabetes or type 2 diabetes to an “Old Stone Age” diet (lean meat, fish, fruits, vegetables, root vegetables, eggs, nuts) or to a “Mediterranean” diet (whole grains, low-fat dairy foods, vegetables, fruits, fish, oils, margarine).

After 12 weeks, the Paleo eaters had lost no more weight than those on the Mediterranean diet. However, the Paleo group did have lower blood sugar levels after a glucose tolerance test, which measures how well insulin controls blood sugar.

Two years later, the same researchers looked at 13 men and women in their 60s with type 2 diabetes. The volunteers were told to eat a Paleo diet for three months and then a standard diet for people with diabetes for three months, or vice versa. The Paleo diet had more fruits, vegetables, lean meat, fish, nuts, and eggs, and no grains, dairy, beans, refined fats, sugar, candy, soft drinks, or beer.

They ended up eating 300 fewer calories a day on the Paleo diet, which may explain why they lost seven more pounds during those three months. And their triglycerides were lower. But there were no differences in blood sugar levels after a glucose tolerance test.

The bigger question: What happens over the long run? At least three trials have compared diets that were either high or low in protein, carbohydrates, or fat—such as Atkins, Ornish, Weight Watchers, and The Zone—on a total of more than 1,200 people.

After one or two years, none of the diets outshined the others. What mattered most was whether people stuck to them. (The more extreme diets—like the high-protein Atkins and the low-fat Ornish—were the hardest to stay on.)

The bottom line: There’s no good evidence that the Paleo diet will make those extra pounds vanish.

Sources: Diabetes 33: 596, 1984. Eur. J. Clin. Nutr. 62: 682, 2008. Eur. J. Clin. Nutr. 63: 947, 2009. Diabetologia 50: 1795, 2007. Cardiovasc. Diabetol. 8: 35, 2009. JAMA 293: 43, 2005. N. Engl. J. Med. 360: 859, 2009. Ann. Intern. Med. 153: 147, 2010.

11 Replies to “Evidence for the Paleo Diet and Weight Loss?”

  1. I would have no confidence or ever consider any diet that includes eating the dead flesh of animals.

  2. This is a little confusing.It sounds like some of the diets did outshine the others. Those that were easiest to stick to. Which diet were people most successful at sticking to in the long run?

  3. I would choose Paleo diet, but exclude most of high sugary fruits, and have fresh or frozen berries only.

  4. I think the studies missed the point. The Paleo Diet as I inderstand it, is to reduce inflammation thus, which diet restores markers of inflammation to normal. Of course the individuals who eat the least calories are going to loose weight. A person could eat less calories on only ice cream and loose weight conceivably. I doubt a glucose tolerance test would reveal anything with respect to diet changes. The glucose load given at the onset of the test is what the body processes. The better question is whether any diet resets hormones that have been activated in the DNA to cause total remission of a disease and how long does it take eating that diet to see results? While weight loss is a factor in this process it certainly should not be isolated, and published, as the lay public simply reads into these type of articles that in general the diet does not work, so why bother. Admitting in the article that weight loss is only one factor in improving health, and the diets may,indeed, need more research to determine their effect on disease should be emhasized.

  5. And to this report you can include the recent study findings that the “original” followers of the Paleo diet showed evidence of cardiovascular disease–they do not appear to have been any healthier from a cardiovascular point of view than people living today.

  6. There is no one diet that is perfect for everyone, we are all different. I agree with this article that the important thing is to stick to whatever eating plan you choose and cut back on processed foods, sugars and fats.AND load up on veggies and eat your fruit DON’T drink it! Bon appetite!

  7. Absurd article.

    The article cites that people ended up eating 300 fewer calories a day on the Paleo diet, and losing 7 more pounds (which is a lot!).

    But then the article absurdly discounts Paleo by looking at Atkins, Ornish, Weight Watchers, and The Zone. None of which are Paleo.

  8. The study cited regarding the comparison of Atkins, Weight Watchers, Ornish and the Zone is flawed. It suggests that an Ornish diet is 30% fat. That is FAR from an Ornish diet. It would be like cutting smoking cigarettes from 3 packs a day to 2 packs a day. Going to a 30% fat diet does not give any advantage. Furthermore there are differing fats relative to health. It could be argued that a diet high in fat of a whole foods unprocessed type might have value. That is not what the population generally eats. Ornish wouldn’t even think the study using his name has merit. If you truly compare a whole foods plant based diet low in calories that are based on fats that are not processed, i.e. nuts, seed, avocados you would have a good study. There are actually a lot of science behind Ornish findings including reversal of heart disease and prostate cancer. This was a poorly written article.

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