By Mark Mahoney
Much of the advice we hear from the experts on diet and health is often attacked as being flawed or faulty.
Critics will denounce expert dietary advice as being based on weak “observational” studies that cannot prove cause and effect (thanks, in part to the food industry). Those types of studies are not necessarily weak, and most advice is also based on the gold standard of scientific research, randomized clinical trials. Here is Part 2 of a review of five‘game-changing’ studies that support expert dietary advice. Click here for Part 1.
The Diabetes Prevention Program
A somewhat startling fact not known by many is that one out of three adults now has prediabetes and nine out of 10 don’t know it.
The Centers for Disease Control and Prevention (CDC) has some good news looking toward addressing this issue. “The CDC-led National Diabetes Prevention Program can help you make lifestyle changes to prevent or delay type 2 diabetes and other serious health problems.”
“Through the program, you can lower your risk of developing type 2 diabetes by as much as 58 percent (71 percent if you’re over age 60”).
The Diabetes Prevention Program consisted of a trial that randomly assigned 3,234 people with prediabetes to take a placebo or metformin (a drug that lowers blood sugar) or to a “lifestyle” group.
Goals of the lifestyle group consisted of losing excess weight and exercising for at least 2 and one-half hours a week.
Grams of fat consumed was counted by participants, as this was easier than counting calories.
Nearly three years later, the average lifestyle participant had lost only 12 pounds and only 58 percent had met the exercise goal. It was noteworthy that these individuals were able to slash their risk of diabetes by 58 percent, far more than the metformin group, which lowered their risk by 31 percent.
According to DPP researcher, Judith Wylie-Rosett, head of the division of health promotion and nutrition research at the Albert Einstein College of Medicine in New York, “…people in the lifestyle group still had a 27 percent lower risk of diabetes than the placebo group 15 years later, even though many had regained the lost weight.”
Researchers are still tracking participants and what was originally a trial has developed into a lifestyle program that’s reimbursed by Medicare, according to Wylie-Rosett.
The DRINK Study
The question of sugary drinks and weight gain was answered in the affirmative by the DRINK trial in 2012.
Mostly normal weight Dutch Children (641 individuals) were assigned randomly either a daily 8-oz. drink sweetened with sugar (104 calories) or artificial sweeteners (0 calories) at school daily. Neither the children nor the investigators had knowledge of who got which drinks.
The question related to whether the children who got zero calories would sense the difference and compensate by eating more calories from another source.
Results after one and one-half years found that the average child who got the sugary drink had gained roughly two pounds more than the average child who received the sugar-free drink.
An observational study was published the same day as the DRINK trial, which tracked 11,000 nurses and health professionals for 12 to 18 years.
Those men and women with a genetic risk for obesity who drank at least one sugary drink per day were four times more likely to become obese than those who drank less than one sugary drink a month, according to Martijn Katan, a cardiovascular disease expert and emeritus professor of nutrition at Vrije Universiteit in Amsterdam.
Furthermore, Katan notes, “Sugary drinks make you fat. They circumvent your innate mechanisms for keeping your body weight stable. If you eat beans or whole wheat bread, they’re not fattening because you feel full so you don’t eat other things.”
“Drinking sugary drinks — including fruit juices will slip into one’s body and you’ll keep on eating as much as you usually do, They’re like burglars, robbing you of your leanness since you don’t notice them coming in,” says Katan.
The Pounds Lost study was initiated in 2004, looking at what mattered most when one was trying to lose weight: cutting fat, cutting protein or cutting carbs? It was not, by any means, the first or last study to address this issue. Each of the diets cut about 750 calories a day.
Over 800 individuals were enrolled over a two-year study (one of the longest diet trials). The trial was unusual for its duration at that time “…because body weight reaches a low point after about six months in a weight-loss program and then you have weight gain,” according to Frank Sachs, professor of cardiovascular disease prevention at the Harvard T.H. Chan School of Public Health.
Daily meal plans and individual and group sessions were provided to participants to learn about what to eat.
Results of this study noted somewhat unexpected results. Sachs noted that “The composition of fat, carbohydrate and protein in a healthy diet had no effect on weight loss or gain.” And it didn’t affect hunger.
The majority of other studies — typically testing low-carb versus low-fat-diets — have had similar results.
The most recent DIETFITS study randomly assigned 609 people to cut as much fat or carbs as possible from their diets, rather than count calories.
One year of study results noted that each group had lost roughly the same amount of weight, about 12 pounds. It wasn’t a surprising result since both groups cut a similar number of calories — about 500-600 a day, on average.
There was an expectation that individuals with insulin resistance (people with insulin resistance have an increased risk of diabetes) would do better on a low carb diet, which didn’t happen, said Christopher Gardner, professor of medicine at the Stanford University School of Medicine.
That may have been due to the fact that both diets were healthy. Gardner said nobody was supposed to eat added sugars or refined grains and everyone was supposed to eat vegetables. Unfortunately, “Americans get a quarter of their calories from added sugars and refined grains and a woefully low number of calories from vegetables…if you don’t count potatoes.”
The takeaway here is that we need to get Americans to make positive changes toward more vegetable consumption, which would go a long way toward producing a healthier population.
As noted in the conclusion to the Part 1 column, adhering to evidence-based scientific research can lead us to make more informed choices and contribute to a healthier lifestyle and a subsequently improved quality of life.
As we proceed into 2019, consider adopting some of these effecive “game changers” into your life. They work!
Thanks to the Center for Science in the Public Interest, for much of the background content in this blog.
Mark Mahoney has been a Registered Dietitian/Nutritionist (R.D.N.) for over 30 years and completed graduate studies in Public Health at Columbia University. He can be reached at email@example.com.