Bittman changes his tune on Sugar Study, while Mother Jones Doubles Down

There’s been an interesting edit in Marc Bittman’s sugar post, as he has now changed his tune on the PLoS one sugar study, now Bittman acknowledges obesity too is important. That was big of him, it is after all, the most important factor. Maybe my angry letter to the editor had an effect, but he’s grudgingly changed this statement:

In other words, according to this study, obesity doesn’t cause diabetes: sugar does.


In other words, according to this study, it’s not just obesity that can cause diabetes: sugar can cause it, too, irrespective of obesity. And obesity does not always lead to diabetes.

The second sentence is totally unnecessary. Of course obesity doesn’t always cause diabetes, or heart attack or whatever. Nor do cigarettes always cause lung cancer. Nor does sugar intake always lead to obesity or diabetes. But obesity is the primary cause of type two diabetes, just as cigarettes are the primary cause of lung cancer, and who knows what sugar is doing.

Mother Jones, sadly, has decided to double down, calling the PLoS One study the “Best. Diet. Study. Ever.” It’s not, of course. It’s merely interesting and suggestive of an effect. It is not nearly proof of causation. They also laud the Mediterranean diet study (maybe it was supposed to be the Best. Study. Ever.?), however, they again show they’re not actually reading these papers because if you read our coverage of the study you’d know they didn’t actually study the Mediterranean diet! In a case of the blind leading the blind, they quote Bittman’s misinformed piece on the Mediterranean diet study

Let’s cut to the chase: The diet that seems so valuable is our old friend the “Mediterranean” diet (not that many Mediterraneans actually eat this way). It’s as straightforward as it is un-American: low in red meat, low in sugar and hyperprocessed carbs, low in junk. High in just about everything else — healthful fat (especially olive oil), vegetables, fruits, legumes and what the people who designed the diet determined to be beneficial, or at least less-harmful, animal products; in this case fish, eggs and low-fat dairy.

This is real food, delicious food, mostly easy-to-make food. You can eat this way without guilt and be happy and healthy. Unless you’re committed to a diet big on junk and red meat, or you don’t like to cook, there is little downside

Except for one critical fact. The subjects assigned to the Mediterranean diet did not have lower consumption of red meat, sugar and hyperprocessed carbs, or other junk! If you look at the supplementary data, you see that the subjects took the positive recommendations of the diet (olive oil, nuts, fish), and more or less ignored the negative recommendations (less meat, less spreadable fats/butter, less baked goods). If you look at figures like supplementary S6, the study groups did not change their diets in these categories relative to the controls, so the effects on their cardiovascular events relative to controls aren’t likely to be from the diet recommendations. When there were changes relative to baseline, even when statistically significant, the changes were tiny.

The participants in this study actually had a very high fat intake, about 35-40% of calories across all groups. And while there was a statistically-significant decrease in cardiovascular events like stroke and heart attack in both study groups (Med + olive oil, Med + nuts), only one arm of the so-called Mediterranean diet (Med + Olive oil) had a non-significant decrease in mortality, while the other arm (Med + Nuts) had a similar curve compared to the “do nothing” control. My interpretation of this, and it’s fine to be critical of it, is that this isn’t that meaningful. If anything, the only variable correlating with decrease in mortality was excess olive oil consumption (> 4 tbsp/day), not the Mediterranean diet. Either that, or eating nuts cancels out the beneficial effects of the diet on mortality.

This is why people always dump on nutrition science when it appears to change every 10 years. Results get overblown, and when the inevitable regression towards the mean occurs, we get blamed for it. The reality is, the press coverage of science is extremely poor, and there is not adequate critical analysis and presentation of results to their audience.