Study confirms: Don't reward yourself for calories burned for lost weight

Overweight women who exercised one to two hours a week lost several pounds in six months without dieting, a study shows. But those who exercised the most — about three hours a week — didn't lose as much as they should have, possibly because they increased the calories they consumed. "There is a great lesson here: People generally overestimate the calories they are burning with exercise, and they may reward themselves by eating more," says lead researcher Tim Church, director of preventive-medicine research at the Pennington Biomedical Research Center in Baton Rouge.

If a person runs for an hour then goes out to have a large high-calorie coffee drink and a large muffin, she probably consumed more calories than she burned, he says. For the latest study, Church and colleagues recruited 411 overweight or obese sedentary women, average age 57. Some of the women were told not to change their level of physical activity. The others were divided into three groups and instructed to do different amounts each week. They rotated walking briskly on a treadmill at a fitness center with riding a stationary bike.

Their workouts were monitored closely by the researchers, and the women were asked not to change their eating habits during the study.

At the end of six months, one group of exercisers was doing an average of 72 minutes of moderate physical activity a week; another group was doing about 136 minutes (a little more than two hours); and the third was doing 194 minutes (slightly more than three hours).

The findings reported in PLoSONE, a Public Library of Science online journal:

• Women who did 72 minutes of physical activity a week lost 2 to 3 pounds in six months, which was what was expected from the amount of exercise they were doing.

• Those doing more than two hours of activity a week lost slightly more than 4 pounds in that time, which also was what was expected.

• Those who did three hours of activity a week lost only about 2 to 3 pounds, but they should have lost almost 6 pounds from the increase in physical activity.

• Everyone who exercised lost dangerous belly fat. Those who didn't lose weight dropped about an inch around the middle. Those who did lose weight trimmed an average of 2 inches around the waist.

This confirms other research that physical activity alone can contribute to some weight loss. Another recent study showed that women who increased their activity level by an additional 3,500 steps a day lost 5 pounds during the year. Men who added that many steps lost 8½ pounds in a year.

Another study showed that when obese women improved their eating habits and walked briskly for an additional 50 minutes to an hour a day, they lost about 10% of their body weight in six months.

Church says a growing body of evidence shows that physical activity decreases dangerous abdominal fat.

"Exercise without weight loss has a benefit to your waist, but exercise with weight loss has even more benefit to your waist," he says. This study did not include men, but he says other research he has done shows the same phenomenon in men.

The loss of belly fat through exercise is important because excess abdominal fat is considered a risk factor for many chronic diseases, including heart disease, diabetes, stroke and some types of cancer, Church says.

Experts believe the fat cells deep in the abdomen are harmful because they secrete chemicals that play a role in a number of diseases. The cells produce about three times more bad chemicals than subcutaneous fat, the stuff you can pinch right under your skin, Church says. "Plus, the plumbing of visceral fat drains directly to the liver, allowing the bad chemicals to directly interfere with the liver's ability to metabolize blood sugar and cholesterol."

In addition to lowering the risk of many serious medical conditions, regular physical activity also improves quality of life by reducing stress, depression and anxiety, and by improving bone and joint health, sex drive, sleep and memory, Church says.By Nanci Hellmich, USA TODAY

Metabolic Syndrome Triggered by Overeating, Not Obesity

Overeating, not the obesity it causes, is the actual cause of metabolic syndrome, suggests a study with mice by researchers at the University of Texas Southwestern Medical Center at Dallas.

Metabolic syndrome is a collection of health factors that increase the risk of developing insulin resistance, fatty liver, heart disease and type 2 diabetes.

This study was among the first to propose that weight gain is an early symptom, not a direct cause, of metabolic syndrome, the researchers said.

"Most people today think that obesity itself causes metabolic syndrome," senior author Dr. Roger Unger, professor of internal medicine, said in a prepared statement. "We're ingrained to think obesity is the cause of all health problems, when, in fact, it is the spillover of fat into organs other than fat cells that damages these organs, such as the heart and the liver. Depositing fatty molecules in fat cells where they belong actually delays that harmful spillover."

In this study, Under and his colleagues compared normal mice to mice that were genetically altered to prevent their fat cells from expanding. Both groups of mice were overfed.

The normal mice got fat but didn't develop signs of metabolic syndrome until after about seven weeks of overeating. The genetically altered mice stayed slim but became seriously ill within a few weeks and displayed evidence of severe heart problems and major increases in blood sugar levels eight weeks before minimal heart problems developed in the normal mice, the researchers said.

The genetically altered mice showed significant damage to heart cells and to the insulin-secreting cells in the pancreas. They also got sick quicker, because the extra calories they consumed weren't stored in fat cells, but rather in other tissues, the researchers said.

The study was published online in the journal Proceedings of the National Academy of Sciences.

The exact cause of metabolic syndrome, which affects about 50 million Americans, is unknown, but lack of exercise and obesity have been tagged as the primary underlying contributors to the development of the condition, according to background information in the study.

Canadian cancer survivors obese and inactive: study

Cancer survivors in Canada are more likely to be obese and less likely to exercise than the rest of the population -- putting themselves at risk of having their cancers come back, researchers said on Monday.

The trends, likely to be seen in cancer survivors around the world, suggest patients need help and support in staying active and keeping the weight off, said Kerry Courneya of the University of Alberta in Edmonton, who led the study.

"It's a challenge for all of us to eat properly and exercise, and it may be especially challenging for cancer survivors who have been through difficult treatments and may have lingering health issues," Courneya said in a statement.

"But eating well and exercising are two of the best things we can do for our mental and physical health, even in trying times. Rest is rarely the best medicine for any health condition."

Courneya and colleagues analyzed data from a 2005 survey of more than 114,000 adults.

Fewer than 22 percent of former cancer patients described themselves as physically active. This compares with 25 percent of the general Canadian population, they reported in the journal Cancer.

They also found that 18 percent of cancer survivors were medically obese, compared to 15 percent of the general population, and 34 percent were overweight.

Many cancers are linked with obesity and a lack of exercise.

"These findings tell us that we need to look at ways to better support cancer survivors to become more active and to maintain a healthy body weight," Courneya said.

"We know that physical inactivity and obesity are risk factors for developing cancer. These are also risk factors for the recurrence of cancer. Lifestyle is just as important after diagnosis."

The researchers defined someone as physically active if they walked at least an hour a day or did the equivalent in swimming, cycling or some other activity. Inactive people walked or exercised less than 30 minutes a day.

Many Cancer Survivors Are Overweight and Sedentary: Study

A healthy lifestyle may help cancer survivors prevent recurrence of the disease and live longer, yet cancer survivors have rates of obesity and physical inactivity similar to those of the general population, according to new research.

The study, published in the June 1 issue of Cancer, found that less than one-quarter of cancer survivors were regularly physically active, and more than 18 percent were obese.

"We thought this might be a time when people would be particularly motivated to exercise and control weight. But, a cancer diagnosis and treatment didn't seem to stimulate behavior change," said the study's lead author, Kerry Courneya, a professor and Canada Research Chair at the University of Alberta in Edmonton, Canada.

What's troubling is that maintaining a healthy weight and getting regular physical exercise may be even more crucial for cancer survivors than it is for the general public. Some studies have suggested that physical activity and losing weight may help prevent cancer recurrence and improve survival odds.

Additionally, some research suggests that exercise can help reduce fatigue, improve physical functioning and improve quality of life for some cancer survivors.

For the study, Courneya and his colleagues gathered data from the Canadian Community Health Survey. This survey contains information based on interviews of more than 114,000 people in Canada. Details of cancer history, weight, height and physical activity were all supplied by the respondents.

General population statistics for Canada find that 37 percent of people are overweight, and 22 percent are obese, according to background information in the study.

Fewer than 22 percent of cancer survivors reported being physically active. The lowest rates of physical activity were found among colorectal cancer survivors, breast cancer survivors and female survivors of melanoma.

Obesity, smoking cuts many US women's life expectancy: study

Life expectancy has declined for many women in the United States, largely due to smoking-related diseases and obesity, a study published Tuesday showed.

Nearly one in five US women saw the number of years they are expected to live decline or hold steady, starting in the 1980s, showed the joint study by the Harvard School of Public Health and the University of Washington.

The study looked at data from more than 2,000 county "units" between 1959 and 2001.

In around 1,000 of those counties -- mainly poor, rural areas -- life expectancy for women dropped starting in the 1980s, "primarily because of chronic diseases related to smoking, overweight and obesity, and high blood pressure," according to the study.

In the United States as a whole, in contrast, life expectancy for women rose by more than six years and for men by more than seven years during the same period, it showed.

"There is now evidence that there are large parts of the population in the United States whose health has been getting worse for about two decades," Majid Ezzati, associate professor of international health at the Harvard School of Public Health, and lead author of the study, said in a statement.

Worst affected by the downturn in longevity were the south -- the region hardest hit by poverty, according to the US Census Bureau -- the Appalachians, southern parts of the Midwest and areas of Texas.

Men in the same areas also saw a drop in life expectancy, but numbers were less alarming than among women -- only four percent -- and the fall was attributed to different causes, mainly HIV/AIDS and homicide.

"Life expectancy decline is something that has traditionally been considered a sign that the health and social systems have failed, as has been the case in parts of Africa and Eastern Europe," said the study's co-author Christopher Murray, director of the Institute for Health Metrics and Evaluation at the University of Washington.

"The fact that this is happening to a large number of Americans should be a sign that the US health system needs serious rethinking," he added.