Field Notes

Defining Moderation May Vary by Individual

Though eating in moderation might be considered practical advice for healthful nutrition, a new University of Georgia study suggests the term’s wide range of interpretations may make it an ineffective guide for losing or maintaining weight.

The more people like a food, the more forgiving their definitions of moderation are, says the study’s lead author Michelle vanDellen, PhD, an assistant professor in the Franklin College of Arts and Sciences department of psychology.

“Moderation is a relative term,” she says. “When people talk about eating in moderation, it doesn’t allow them a clear, concrete way to guide their behavior. For both thin and overweight people, people tend to think of moderation through their own objective lens, and they tend to exaggerate what moderation is.”

The study, published in the journal Appetite, describes the relative meanings attached to moderation based on perceptions. The findings are based on the results of different studies the team conducted in the lab and online.

“We asked people to tell us what they think moderation is, in terms of quantity,” says vanDellen, an expert on self-control. “For instance, the research team asked participants to define how many cookies would be moderation, how many would be indulgence, and how many would be considered what you should eat.

“People do think of moderation as less than overeating, so it does suggest less consumption. But they do think of it as more than what they should eat. So moderation is more forgiving of their current desires. … The more you like a food, the more of it you think you can eat in moderation.”

The study adds to the growing body of literature that suggests people are poor judges of the amounts of food they’re eating. And in terms of the rising rates of obesity, vanDellen notes a general backlash against dieting.

“People are now saying, ‘Diets don’t work; you shouldn’t go on a diet. You should just live by the rule of moderation,’” she says. “This is an increasingly popular belief. There are entire healthy eating movements oriented toward this idea of moderation.”

She cites the many stigmatizing features associated with judging people for being overweight as one possible source of this reaction. These movements are very sensitive to the negative effects of those stigmas.

“But those movements assume people can actually be good judges of what they’re eating and what constitutes an appropriate amount,” vanDellen says. “The fact that those movements are gaining in popularity at the same time we are learning people are not good at estimating things like moderation suggests there’s a lot of room to be concerned about growing rates of obesity.”

— Source: University of Georgia


Eye Study Shows Benefits of Controlling Diabetes

People with type 2 diabetes who intensively controlled their blood sugar level during the landmark Action to Control Cardiovascular Risk in Diabetes (ACCORD) Trial Eye Study were found to have cut their risk of diabetic retinopathy in half in a follow-up analysis conducted four years after stopping intensive therapy. Investigators who led the ACCORD Follow-on Eye Study (ACCORDION) announced the results in New Orleans at the American Diabetes Association annual meeting.

“This study sends a powerful message to people with type 2 diabetes who worry about losing vision,” says Emily Chew, MD, deputy director of the National Eye Institute (NEI) division of epidemiology and clinical applications and lead author of the study report, published in Diabetes Care. “Well-controlled glycemia, or blood sugar level, has a positive, measurable, and lasting effect on eye health.”

A complication of diabetes, diabetic retinopathy can damage tiny blood vessels in the retina—the light-sensitive tissue in the back of the eye. ACCORDION is a follow-up assessment of diabetic retinopathy progression in 1,310 people who participated in ACCORD, which tested three treatment strategies to reduce the risk of cardiovascular disease among people with longstanding type 2 diabetes. ACCORD tested maintaining near-normal blood sugar levels (intensive glycemic control); improving blood lipid levels, such as lowering LDL cholesterol and triglycerides and raising HDL cholesterol; and lowering blood pressure.

The treatment phase of the glycemic control portion of ACCORD had been planned to last 5.6 years but was stopped at 3.5 years due to an increase in death among participants in the intensive glycemic control group. The blood pressure and blood lipid portions of ACCORD continued. Tight control successfully reduced glycemia to an average 6.4% A1c, compared with 7.7% among participants on standard glycemic control therapy.

Although it failed to reduce cardiovascular disease risk, eg, heart attack and stroke, the researchers found that the therapy had cut retinopathy progression by about one-third by the end of ACCORD. Investigators considered progression to have occurred if a participant required laser surgery for diabetic retinopathy, required a vitrectomy—a procedure used to remove the gellike fluid of the eye—or advanced three or more steps on the Early Treatment Diabetic Retinopathy Study (ETDRS) Severity Scale. The ETDRS Severity Scale uses photographs of the retina to rate disease severity from 1 (no disease) to 17 (high-risk of progression in both eyes).

ACCORDION reassessed diabetic retinopathy about four years after the intensive glycemic control portion of the study had ended—eight years after enrollment in ACCORD. By then, average A1c was nearly the same: 7.8% for the intensive therapy group and 7.9% for the standard therapy group. However, diabetic retinopathy had advanced in only 5.8% of participants in the intensive therapy group since enrollment in ACCORD, compared with 12.7% in the standard therapy group.

“Despite this equalization of glycemic control in the two groups, there continued to be an approximately 50% risk reduction of further retinopathy progression, a phenomenon termed metabolic memory,” says Frederick L. Ferris III, MD, NEI clinical director, who wasn’t involved in the study.

Other clinical trials have reported the phenomenon, also known as the legacy effect. Participants with type 1 diabetes who received intensive glycemic therapy in the 10-year-long Diabetes Control and Complications Trial on average had 50% less progression of diabetic retinopathy three decades later. A similar trend was seen in the United Kingdom Prospective Diabetes Project, a study of people with newly diagnosed type 2 diabetes.

Results from ACCORDION suggest that lowering blood glucose can reduce progression of retinal disease relatively late in the course of type 2 diabetes and that even short-term changes in glucose have an effect. The findings add to mounting evidence that tight glycemic control has positive, long-lasting effects on small blood vessels. Other follow-up studies of ACCORD participants have observed a legacy effect similar to ACCORDION in kidney and peripheral nerve health, which also involve small blood vessels. But the benefits of intensive glycemic therapy must be weighed against the potential risks—most notably the increased risk of death observed in ACCORD. Investigators have been unable to determine a cause for the increase, which wasn’t seen in other trials.

Results also point to a possible role for ongoing use of fenofibrate to treat diabetic retinopathy, if taken regularly. The blood lipid and blood pressure portions of ACCORD concluded at 5.6 years. Neither strategy reduced cardiovascular disease. However, fenofibrate, a drug that raises HDL cholesterol, decreased diabetic retinopathy progression by about one-third during ACCORD. ACCORDION investigators found fenofibrate had no lasting benefit three years after the drug was discontinued.

But based on ACCORD findings, fenofibrate might be worth taking to control diabetic retinopathy progression. Other countries, including Australia, have approved fenofibrate for treating diabetic retinopathy, but not the United States, Chew says. The NEI-funded Diabetic Retinopathy Clinical Research Network is currently planning a clinical trial to further explore ongoing use of fenofibrate to control diabetic retinopathy.

Diabetic retinopathy affects about 7.7 million Americans and is the leading cause of vision loss among working-age Americans. Diabetic retinopathy can cause blood vessels to swell and leak fluid, sometimes distorting vision. Proliferative diabetic retinopathy, an advanced stage of the disease, occurs when abnormal blood vessels appear on the surface of the retina. These abnormal blood vessels are prone to bleeding and lead to the formation of scar tissue, sometimes causing retinal detachment and permanent vision loss.

— Source: National Eye Institute