5 Nutrition Myths That Just Won’t Die

Nutrition Myths

By Maryann Tomovich Jacobsen, MS, RD

In my 15 years as a registered dietitian I have seen nutrition myths come and go. But some myths demonstrate particular staying power. I thought it would be fun to list nutrition myths that continue to live on despite the lack of research to substantiate them.

1. Don’t eat past 6 p.m.: It’s common for people to pick an arbitrary time, like 6 p.m., to stop eating for the day. But there is no research that eating dinner at a particular time in the early evening makes a difference.

What does matter is how much someone eats and whether or not they eat during sleeping hours. There is a tendency for people to eat more at night or snack non-stop while watching TV. Many may stay up so late that they get hungry and eat again before bed. In mice, eating at times one should be sleeping results in increased weight even when calorie intake is the same. Researchers believe this is why shift workers tend to gain extra weight.

Bottom line: Eat a sensible dinner at the table at a time that works for you, don’t stuff yourself, and go to bed early enough to allow for a good night’s sleep.

2. Drink eight 8-oz glasses of water every day: This myth might win the prize for the longest lasting before it was finally disproved. I, too, used to tell people to drink this much water (shame on me!). But a 2002 study in the American Journal of Physiology found no evidence of benefits from consuming large amounts of water.

In 2004, the Institute of Medicine came out with recommendations dropping set amounts of fluid and, instead, suggested using thirst as a guide. Not only that, but all beverages count as fluid — even caffeine-containing beverages such as coffee (not quite the diuretic we thought it was).

Bottom line: no need to force feed water, but keep some on hand to quench your thirst throughout the day.

3. Carbs are bad: Just when we finally debunked the myth that fat is bad, many now believe that carbs like pasta, potatoes and bread don’t belong in a healthy diet. Much of this carbs-are-bad myth comes from exaggerations about the body responding with high blood sugars and surging insulin levels, causing carbs to be stored as fat.

But it’s not just what we eat in terms of carbs but how we eat them. For example, a 2006 study published in the Journal of Nutrition shows that mixing protein, fat and fiber with a meal substantially lowers the glycemic response.

Bottom line: Make at least half your grains whole and enjoy your favorite refined grains with a balanced meal (i.e., salad topped with protein, olive oil-based dressing and a French roll).

4. More protein will build muscles. A coworker once asked me if she really needed the 150g of protein her personal trainer recommended. She was trying to build muscle mass (but not too much) and questioned this because it was so difficult for her to make it work.

While the American College of Sports Nutrition does recommend more protein in the active person, it’s not as much as people think about 1.2-1.7g/kg per body weight vs. 0.8g/kg for the general population. For my 120-pound friend, that would be about 80g of protein per day (at 1.5g/kg). The key is to make sure you have enough non-protein calories (fat and carbs) so the protein is utilized for muscles and not energy needs. Also, timing of protein intake matters as consuming some after a workout promotes muscle repair (protein bar or cheese and crackers).

Bottom line: Get the right amount of quality protein, but not too much.

5. Multivitamins are good insurance: For years people have consumed multivitamins for “dietary insurance.” Yet according to the 2010 Dietary Guidelines for Americans, there is little evidence that multivitamins prevent chronic disease. That’s not all — there may even be some negatives to consuming too much of certain nutrients like folic acid, but more research is needed.

Instead of blindly taking a multivitamin, look at your diet for nutrient gaps. First, check the amount of vitamins and minerals you are getting from fortified foods like cereals, bars and snack items. Are you eating from all the food groups? Take a food first approach and if you can’t make the improvement, look for supplements to meet the gaps. Sometimes that might be a multivitamin but other times it might be single nutrients like vitamin D or omega-3 fatty acids. It’s still recommended that women of childbearing age take a multivitamin with folic acid to help prevent neural tube defects.

Bottom line: Don’t take vitamins for insurance. Understand what you are getting from the supplements you take and why.

What nutrition myths have you seen persist? Share them here or visit us on facebook.


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