In 1984, Time magazine famously featured a sad face made of fried eggs and bacon on its cover. According to experts quoted in the article, fat was the macronutrient villain, squarely blocking the gate to lower BMIs and better cardiovascular health. Thirty years later, Time again tackled the subject of dietary fat, this time showing a graceful curl of butter on the cover. Fats were now considered a sound nutritional choice, the magazine reported, while carbohydrates were unfairly demonized as a major contributor to obesity, diabetes, and a host of other ailments.
When Time‘s “fats are good, carbohydrates are bad” article was published, the public’s love affair with low carbohydrate diets and the attendant misconception of a causal relationship between carbohydrate consumption and adiposity were already firmly rooted. The Doctor’s Quick Weight Loss Diet and Dr. Robert Atkins’ early version of his now famous diet were among the first to gain notice in the US, but consumers were understandably frightened by the potential health risks of these diets due to the high levels of protein and fat. It was not until the late 1990s, arguably with a big boost from the internet, that diets restricting carbohydrates began to enjoy widespread popularity.
Many of these diets call for no more than 20 percent of daily calories from carbohydrates, a dramatic reduction from the recommended 45 to 65 percent. But, it is not just the reduction in carbohydrates, but the increased protein that seems to attract consumers to diets like Atkins, the Zone, South Beach, and Paleo. Nine out of 10 people surveyed by the Institute of Food Technologists (IFT) believe that protein helps build muscle and two out of three people believe that protein aids weight loss. Meanwhile, 37 percent of grocery shoppers say they seek out low sugar products and 28 percent specifically try to avoid high fructose corn syrup, according to IFT.
High fructose corn syrup (HFCS) — and by association, fructose — are often singled out as the most unhealthful of all carbohydrates, even though there is no strong scientific evidence to back up that claim. A 2013 review found that many studies supporting a correlation between fructose consumption and cardiovascular disease or non-alcoholic fatty liver disease had tested the effects of very high doses of fructose rather than the much lower levels normally consumed. And, the review’s author points out that while it is true that rates of obesity have risen, HFCS consumption has actually declined, so no positive correlation can be established.
Unfortunately for adherents to elimination diets, research does not support the efficacy of overemphasizing one macronutrient over another to reduce weight or improve metabolic markers. Studies comparing three isocaloric diets — high carbohydrate, high protein, high fat — have tended to find participants lose more weight on the high protein diet, but the difference was insignificant and usually short-lived . In a meta-analysis of 15 long-term randomized controlled trials, researchers determined that high protein diets had a neutral effect on blood glucose control, obesity, and markers for cardiovascular disease (//bit.ly/2aBkJ72).
There are also risks associated with low carbohydrate/high protein diets. They include minor annoyances like bad breath to major health concerns such as the possibility of kidney damage and, if the diet is also high in fat, possible damage to the cardiovascular system.
Despite the drawbacks of low carbohydrate diets, healthcare professionals may find patients and clients are reluctant to give up them up, particularly if they have experienced some short-term success and have been influenced by misinformation on the internet.
Professional guidance should include sharing a list of reliable nutrition-related internet resources, encouraging daily exercise, and designing an eating plan that is varied, moderate, balanced, and based on currently recommended daily macronutrient ranges of carbohydrate (45 to 65 percent), protein (10 to 35 percent) and fat (20 to 35 percent). These ranges allow sufficient flexibility to fine tune the amount of each macronutrient in the diet to meet individual tastes and needs. The USDA’s SuperTracker site gives patients and clients a convenient and cost-free way to track their food intake and nutritional status.
Ellen Stokes, MS, RD, LD is an award-winning video producer, director, and writer in addition to being a registered dietitian. Ellen writes and creates videos about nutrition education, food safety, menu planning, grocery shopping, and healthful cooking on a budget. Ellen has worked with organizations and companies including WebMD, the Partnership for Food Safety Education, and the University of Georgia Food Science Department. Ellen formerly worked for CNN as a writer and producer and teaches food safety and nutrition for Georgia State University. Check her out on Twitter @EllenS_RD.