Three-week diet/exercise study shows 50 percent reversal in
metabolic syndrome, Type 2 diabetes
Obese and overweight individuals suffering metabolic syndrome
and Type 2 diabetes showed significant health improvements
after only three weeks of diet and moderate exercise even
though the participants remained overweight.
"The study shows, contrary to common belief, that Type 2
diabetes and metabolic syndrome can be reversed solely
through lifestyle changes," according to lead researcher
Christian Roberts of University of California, Los Angeles.
"This regimen reversed a clinical diagnosis of Type 2
diabetes or metabolic syndrome in about half the
participants who had either of those conditions. However,
the regimen may not have reversed damage such as plaque
development in the arteries," Roberts said. "However, if
Type 2 diabetes and metabolic syndrome continue to be
controlled, further damage would likely be minimized and
it's plausible that continuing to follow the program
long-term may result in reversal of atherosclerosis."
"The results are all the more interesting because the changes
occurred in the absence of major weight loss, challenging
the commonly held belief that individuals must normalize
their weight before achieving health benefits," Roberts
said. Participants did lose two to three pounds per week,
but they were still obese after the 3-week study.
The study, "Effect of a diet and exercise intervention on
oxidative stress, inflammation, MMP-9, and monocyte
chemotactic activity in men with metabolic syndrome
factors," is in the online edition of the Journal of Applied
Physiology published by the American Physiological Society.
Researchers were Christian K. Roberts, Dean Won, Sandeep
Pruthi, Silvia Kurtovic, and R. James Barnard, all of UCLA;
Ram K. Sindhu of Charles R. Drew University, Los Angeles;
and Nosratola D. Vaziri of University of California, Irvine.
The study involved 31 men who ate a high-fiber, low-fat diet
with no limit to the number of calories they could consume.
The participants also did 45-60 minutes of aerobic exercise
per day on a treadmill.
Fifteen of the men had metabolic syndrome, a condition that
is characterized by excessive abdominal fat, insulin
resistance, and blood fat disorders such as high levels of
triglycerides (fat in the blood) or low levels of HDL (high
density lipoprotein, or "good" cholesterol). Thirteen of the
participants had Type 2 diabetes. There was also some
overlap between the two groups and some participants who had
neither metabolic syndrome nor Type 2 diabetes, but were
overweight or obese.
"The diet, combined with moderate exercise, improved many
factors that contribute to heart disease and that are
indirect measures of plaque progression in the arteries,
including insulin resistance, high cholesterol, and markers
of developing atherosclerosis," Roberts said. "The approach
used in this experiment of combining exercise with a diet of
unlimited calories is unusual."
Low-calorie foods
The participants in the current study, who ranged in age from
46 to 76 years old, took part in a 21-day residential
program at the Pritikin Longevity Center, formerly in Santa
Monica, combining the Pritikin diet and exercise program.
The daily diet was low fat (12-15% of calories), moderate
protein (15-20% of calories), and high in unrefined
carbohydrates (65-70% of calories) and fiber (more than 40
grams).
Natural foods -- whole grains (five or more servings daily),
vegetables (four or more servings), and fruits (three or
more servings) -- were the main source of daily
carbohydrates. The sources of protein were plants (such as
soy, beans, and nuts), nonfat dairy (up to two servings
daily), and fish and poultry (3.5-ounce portion once a week
and in soups and casseroles twice a week). The remainder of
the calories came from fat with a
polyunsaturated-to-saturated fatty acid ratio of 2.4 to 1.
"Aside from meat and dairy, the study participants could eat
as much as they wanted," Roberts said. "Because the food was
not as high calorie as a typical American diet, the
participants ate less before feeling full. This is a
departure from most diets, which usually leave the dieter
feeling hungry," he said.
The men also exercised daily on a treadmill, including level
and graded walking, for 45-60 minutes. The exercise program
was tailored to ensure each individual reached 70-85% of
maximum heart rate.
Next steps
Trials outside the laboratory environment are needed to test
the regimen in the general population. "The findings are
likely generalizable, although the magnitude of change is
proportional to the degree of abnormality when the person
begins the regimen," Roberts added.
Scientists also need to determine whether long-term lifestyle
change can prevent or reverse end-organ damage noted in
those with metabolic syndrome or Type 2 diabetes, Roberts
said. These changes may be difficult to make but the payoff
for individuals and society could be enormous.
Further studies are also needed in those who are at risk for
metabolic syndrome or Type 2 diabetes. Individuals should
still be tested to see if Type 2 diabetes and metabolic
syndrome can be prevented in the first place. Individuals
may be considered healthy before developing metabolic
syndrome but looking healthy does not necessarily mean being
healthy, he noted.