Juicing, coconut oil and gluten-free foods are but a few emerging dietary crazes across the world, but evidence suggests these trends could actually be detrimental to a good diet.
These conclusions are part of a new review of the latest scientific evidence on food and nutrition that was conducted to shed some light on the latest diet fads.
Confusion over nutrition
"There is widespread confusion in terms of nutrition. Every day someone says something is good, and then the next day they say it's bad," said review lead author Dr Andrew Freeman, co-chair of the American College of Cardiology's Lifestyle and Nutrition Work Group.
"Our purpose was to do our best to give clinicians the tools they need to help their patients," said Freeman, who is also director of cardiovascular prevention and wellness at National Jewish Health in Denver.
The new paper was published in the Journal of the American College of Cardiology.
He and his colleagues reviewed medical evidence related to overall healthy eating patterns and specific dietary fads that are currently popular in the United States. The researchers found that the following five fads aren't so healthy after all:
Much of the good fibre is lost in the process of juicing, says Theresa Marais, a registered dietitian in private practice. “This is necessary for the gut and to prevent constipation. People also add too many things such as yogurt and protein powders into the mix,” Marais told Health24. Juicing removes the juice from fresh fruits or vegetables, producing liquid that contains most of the vitamins, minerals and chemicals found in whole fruit. But, whole fruits and vegetables have valuable fibre that's removed during most juicing.
People who juice tend to drink more concentrated calories without feeling as full afterward. "You're leaving behind most of the nutrients, you're leaving behind the fibre and research has shown that when you drink calories they aren't as satiating as when you chew them," said Dr Alice Lichtenstein. She's director of the Cardiovascular Nutrition Laboratory at Tufts University in Boston.
2. High-antioxidant diets
By the same token, high-dose antioxidant dietary supplements don't appear to benefit people any more than simply eating foods rich in antioxidants. "Every time we extract things from plants, we usually don't get the same benefit, or sometimes we get a non-benefit, a danger," Freeman said. "If you eat a well-balanced diet, vitamin supplementation is usually not required."
"I would argue all brightly coloured vegetables and fruits are antioxidant-rich nutrient powerhouses," Freeman advises.
Overall, people would be better off with a predominantly plant-based diet that emphasises eating whole unprocessed foods, Freeman advised.
3. Coconut Oil
Coconut oil is a recent health food fad, but it is naturally loaded with unhealthy saturated fats, Freeman and Lichtenstein said. People would do better to use olive and vegetable oils in their cooking, since they contain healthy unsaturated fats. "Everybody is buying tubs and tubs of coconut oil, and the data behind it just doesn't exist," Freeman said.
4. Gluten-free diets
A gluten-free diet can help people with gluten sensitivity or coeliac disease, but is no good for healthy people who can digest grains without any side effects. Whole grains can actually be healthier for people than gluten-free alternatives that are higher in processed carbohydrates, Freeman noted.
Eggs can increase a person's cholesterol levels, although not as much as previously thought, Lichtenstein said. One or two eggs per day likely would have a small effect in most people not at high risk for heart problems or high cholesterol. "When you start going above that, particularly in high-risk individuals, it may be problematic," she said. The saturated fats found in meat and dairy products pose a larger hazard to cholesterol levels, Lichtenstein noted.