Some new research reported last week suggests that all is not well in Low Carb Diet land. According to popular belief, low carb/high fat/high protein diets lead to faster and easier weight loss, and improvement in some health risk measures. In this study from the University of Alabama at Birmingham, obese rats were fed the typical high fat/low carb diet recommended for weight loss. The rats had more damaging and deadly heart attacks compared to rats fed a low fat control diet. The reasons for this effect appear related to increased oxidative stress on heart tissue, and an inability of heart muscle cells to adjust to using ketones for energy, instead of glucose. A high fat diet forces cells to burn more ketones, which are fat metabolism byproducts, for energy. After a heart attack, insulin and glucose would normally help heart cells recover, but the cells’ ability to respond to insulin is impaired by a high fat diet. The message: if you’ve got heart disease, a low carb/high fat, meat-heavy diet may not be your best choice, whether or not you need to lose weight.
And more bad PR for low carb. An editor for MedPage Today examined evidence that low fat/high carb diets are actually superior at improving glucose tolerance for Type 2 diabetics. Dr. George Lundberg notes that the typical advice these days might be for Type 2 diabetics to avoid starch and sugar. But some studies of glucose levels dispute this conventional advice. Dr. Lundberg discusses one study from 2006, comparing a low fat/high carb vegan diet to the standard American Diabetes Association recommendations. The vegan dieters lost more weight and were more likely to lower their medications compared to the official ADA diet plan. Additionally they were more likely to stick with the diet, because they could eat as much as they wanted. This is a key point, because diets that look good on paper are worthless if people can’t stick with them.
Speaking of fat, a study from Canada disputes the widespread belief that nutrition labeling results in healthier food choices and less obesity. Actually, I think we already knew this. The study involved asking subjects from the US, Canada and France questions about the fat content of food products. French respondents knew little compared to the very nutrition-wise Americans. Nevertheless, as the researchers point out, the French have 1/3rd the obesity rate as the Americans. Conclusion: knowledge of nutrition facts has no effect on what people eat. Well, I’m not sure that’s a cause-and-effect relationship. Food and meal customs in France are dramatically different from in the US, whether or not people know a few nutrition facts or read labels. The lack of a nonstop-snacking culture, small portions and vastly lower consumption of sugary soft drinks probably has as much to do with the lower obesity rate. Reading labels isn’t going to fix those American habits. But the study does point out the futility of depending on labels to fix our eating habits. We don’t eat by numbers, or at least most of us don’t, the Food Police being the exception.
Finally, are you lured into buying a product because “ANTIOXIDANTS” is plastered on the front of the package? One professor of nutrition has a message for you: Stop! According to Dr. Carl Keen from the University of California, Davis, the word “antioxidant” should be banned from food labels. He points out that test tube experiments that identify various antioxidants in foods don’t say anything about whether those chemical do any good once you eat them. So-called super fruits, or foods with high ORAC values may not improve health, if the antioxidants in those foods aren’t used in cells for beneficial effects. And so far, there’s very little evidence to back up claims of health benefits. He thinks the money and effort spent measuring amounts of antioxidants in foods would be better spent investigating whether eating them leads to better health outcomes. The whole antioxidant craze is another example of Nutritionism. Eating by numbers — choosing foods because of some antioxidant content — might make you feel like you’re doing something healthy, but it isn’t necessarily going to make you healthier.