Tag Archives: Calories

Low-Carb, Higher-Fat Diets Add No Arterial Health Risks To Obese People Seeking To Lose Weight

OVERWEIGHT and obese people looking to drop some pounds and considering one of the popular low-carbohydrate diets, along with moderate exercise, need not worry that the higher proportion of fat in such a program compared to a low-fat, high-carb diet may harm their arteries, suggests a pair of new studies by heart and vascular researchers at Johns Hopkins.

Dr Kerry J. Stewart

“Overweight and obese people appear to really have options when choosing a weight-loss program, including a low-carb diet, and even if it means eating more fat,” says the studies’ lead investigator exercise physiologist Kerry Stewart, Ed.D.

Stewart, a professor of medicine and director of clinical and research exercise physiology at the Johns Hopkins University School of Medicine and its Heart and Vascular Institute, says his team’s latest analysis is believed to be the first direct comparison of either kind of diet on the effects to vascular health, using the real-life context of 46 people trying to lose weight through diet and moderate exercise.

The research was prompted by concerns from people who wanted to include one of the low-carb, high-fat diets, such as Atkins, South Beach and Zone, as part of their weight-loss program, but were wary of the diets’ higher fat content.

In the first study, presented June 3 at the annual meeting of the American College of Sports Medicine in Denver, the Johns Hopkins team studied 23 men and women, weighing on average 218 pounds (about 99 kg) and participating in a six-month weight-loss program that consisted of moderate aerobic exercise and lifting weights, plus a diet made up of no more than 30 percent of calories from carbs, such as pastas, breads and sugary fruits.  As much as 40 percent of their diet was made up of fats coming from meat, dairy products and nuts.

This low-carb group showed no change after shedding 10 pounds (4.5 kg) in two key measures of vascular health: finger-tip tests of how fast the inner vessel lining in the arteries in the lower arm relaxes after blood flow has been constrained and restored in the upper arm (the so-called reactive hyperemia index of endothelial function), and the augmentation index, a pulse-wave analysis of arterial stiffness.

Low-carb dieters showed no harmful vascular changes, but also on average dropped 10 pounds in 45 days, compared to an equal number of study participants randomly assigned to a low-fat diet. The low-fat group, whose diets consisted of no more than 30 percent from fat and 55 percent from carbs, took on average nearly a month longer, or 70 days, to lose the same amount of weight.

“Our study should help allay the concerns that many people who need to lose weight have about choosing a low-carb diet instead of a low-fat one, and provide re-assurance that both types of diet are effective at weight loss and that a low-carb approach does not seem to pose any immediate risk to vascular health,” says Stewart. “More people should be considering a low-carb diet as a good option,” he adds.

Because the study findings were obtained within three months, Stewart says the effects of eating low-carb, higher-fat diets versus low-fat, high-carb options over a longer period of time remain unknown.

However, Stewart does contend that an over-emphasis on low-fat diets has likely contributed to the obesity epidemic in the United States by encouraging an over-consumption of foods high in carbohydrates. He says high-carb foods are, in general, less filling, and people tend to get carried away with how much low-fat food they can eat. More than half of all American adults are estimated to be overweight, with a body mass index, or BMI, of 26 or higher; a third are considered to be obese, with a BMI of 30 or higher.

Stewart says the key to maintaining healthy blood vessels and vascular function seems ‒ in particular, when moderate exercise is included ‒ less about the type of diet and more about maintaining a healthy body weight without an excessive amount of body fat.

Among the researchers’ other key study findings, presented separately at the conference, was that consuming an extremely high-fat McDonald’s breakfast meal, consisting of two English muffin sandwiches, one with egg and another with sausage, along with hash browns and a decaffeinated beverage, had no immediate or short-term impact on vascular health.  Study participants’ blood vessels were actually less stiff when tested four hours after the meal, while endothelial or blood vessel lining function remained normal.

Researchers added the McDonald’s meal challenge immediately before the start of the six-month investigation to separate any immediate vascular effects from those to be observed in the longer study. They also wanted to see what happened when people ate a higher amount of fat in a single meal than recommended in national guidelines.

Previous research had suggested that such a meal was harmful, but its negative findings could not be confirmed in the Johns Hopkins’ analysis.  The same meal challenge will be repeated at the end of the study, when it is expected that its participants will still have lost considerable weight, despite having eaten more than the recommended amount of fat.

“Even consuming a high-fat meal now and then does not seem to cause any immediate harm to the blood vessels,” says Stewart.  However, he strongly cautions against eating too many such meals because of their high salt and caloric content.  He says this single meal ‒ at over 900 calories and 50 grams of fat ‒ is at least half the maximum daily fat intake recommended by the American Heart Association and nearly half the recommended average daily intake of about 2,000 calories for most adults.

All study participants were between the age of 30 and 65, and healthy, aside from being overweight or obese.  Researchers say that in the first study, because people were monitored for the period they lost the same amount of weight, any observed vascular differences would be due to what they ate.

Source: Johns Hopkins School of Medicine

Watch this video on Low-Carb, High-Fat Diet featuring Dr Mary Vernon.


Diabetes: Vegetarians Better Off Than Non-Vegetarians On All Counts Including Blood Sugar, Blood Pressure, Waist Size, BMI & Blood Fats

People who follow a vegetarian or meat-free diet may be at a lower risk of developing diabetes and heart disease, a new study suggests. The study of lifestyle habits of more than 700 adults showed researchers that 23 out of every 100 vegetarians have at least three metabolic syndrome factors, compared with 39 out of every 100 non-vegetarians and 37 out of every 100 semi-vegetarians.

The researchers measured a suite of factors ‒ blood sugar, blood fats, blood pressure, waist size, and body mass ‒ that when elevated add up to “metabolic syndrome,” and found that vegetarians were lower than non-vegetarians on all counts except cholesterol.

Metabolic syndrome is a combination of health disorders that increase the risk of developing coronary artery disease, stroke, and diabetes. The risk factors include conditions like abdominal obesity, blood fat disorders, elevated blood pressure, insulin resistance or glucose intolerance.

Vegetarianism excludes high-calorie foods and animal products laden with saturated fats. It instead concentrates on foods that give necessary minerals and vitamins that help give diabetics a better chance of blood glucose control. These include whole grains, legumes, fruits and vegetables.

Vegetarian diets are rich in fiber, which has numerous benefits. When a diabetic eats a fiber-rich meal, the desire for further food disappears. Fiber also plays a protective role for pre-diabetics, and can lead to lower daily requirements of insulin amongst type 1 diabetics.

Fiber is well known as being important in the improving blood sugar control, lowering cholesterol levels and providing folate, thereby reducing the risk of complications like heart disease. Considerable research is available as evidence for the role of fiber in diabetes.

Research has shown vegetarian diets promote a healthy weight since they are often lower in calories than non-vegetarian diets. They also improve blood sugar control and insulin response since eating vegetables, fruits, whole grains, legumes and nuts — features of a vegetarian diet — can improve blood sugar control and make your body more responsive to insulin. Most importantly, a vegetarian diet reduces the risk of cardiovascular disease since it is cholesterol-free, low in saturated fat and usually high in soluble fiber.

The new study ‒ published in the journal Diabetes Care ‒ has confirmed that vegetarians are lower than non-vegetarians on all counts including blood sugar, blood pressure, waist size, body mass index (BMI), and blood fats except cholesterol.

The findings show the vegetarians’ average BMI of 25.7 was four points lower than that of non-vegetarians, who, on average, had BMIs close to 30. However, semi-vegetarians fell in the middle. A BMI greater than 25 is considered overweight, and greater than 30 is considered obese. Moreover, the findings suggested that while vegetarians, on average, were 3 years older than the meat-eaters, they were in better shape and health status.

“I was expecting there should be a difference….but I didn’t expect that it would be that much,” lead researcher Nico Rizzo of Loma Linda University was quoted by Reuters as saying, adding he was not sure what’s behind the differences and wondered whether it was primarily the meat intake, the plant food intake or a combination of both.

It’s possible that diet is not the cause because the research showed only an association between food choices and health factors, not cause-and-effect. High BMI, for instance, one of the traits that make up the metabolic syndrome profile, itself contributes to high blood pressure, and indirectly, blood sugar, and thereby potentially raising a person’s risk of heart disease and diabetes.

One of the shortcomings of the study is that the researchers didn’t study the reasons behind the differences between vegetarians and non-vegetarians even though the scientists suggest it may be caused by the meat intake, eating the plant food or a combination of both. The researchers also did not follow the subjects over the long term to see whether those who abstained from meat actually had lower rates of diabetes or heart disease.

The data for this research, which was funded by the National Institutes of Health, came from the Adventist Health Study 2, a long term study of Seventh Day Adventists. This Christian religious group has considerably more vegetarians than the general population.

In this study, 35 percent of the subjects did not eat meat, whereas only about five percent of all Americans are vegetarian. One of the differences Rizzo discovered between the groups was age. Vegetarians, on average, were 3 years older than the meat-eaters. “Even though they’re older, they’re in better shape,” Rizzo said. “That’s something I found quite interesting.”

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