Tag: obesity

New scientific evidence that intermittent fasting has health benefits

On By A.P.In fastingLeave a comment

by Charles Q. Choi

Instead of eating three square meals a day, an eating schedule that involves “intermittent fasting” could help fight not just obesity but many related diseases of modern life, such as diabetes, heart disease, cancer and Alzheimer’s, researchers say.

he advice given on fighting obesity usually focuses on consuming fewer calories and exercising more. The benefits of such foods as vegetables, fruits, nuts, fiber and fish, and the value of reducing or eliminating snacks are often also touted.

However, mounting evidence reveals that other key aspects of diet — when and how often people eat — can also play a major role in health. In fact, the most common eating pattern in modern societies of three meals daily, plus snacks, is abnormal from the perspective of human evolution, an international group of researchers wrote in an article published in the journal Proceedings of the National Academy of Sciences.

More and more research shows that intermittent fasting could have benefits, they said.

“Fasting alone is more powerful in preventing and reversing some diseases than drugs,” said Satchidananda Panda, an associate professor of regulatory biology at the Salk Institute for Biological Studies in San Diego, California, and one of the co-authors of the article.

Ancient hunter-gatherers often ate only intermittently, the researchers noted in their article. This suggests that the ability to function at a high level both physically and mentally during extended periods without food may have been crucial in human evolution, and that the human body may have adapted to perform at its best with intermittent fasting.

Such intermittent fasting could consist of eating 500 calories or less either two days each week, or every other day, or not eating breakfast and lunch several days each week, the researchers said.

Prior research suggests that in animals, intermittent fasting can fend off or even reverse such illnesses as cancer, diabetes, heart disease and neurodegenerative disorders. Animal studies suggest that intermittent fasting provides these benefits by allowing the body to respond better to stress that might otherwise damage it. For example, fasting could starve tumors, reduce inflammation, or improve the removal of damaged molecules and other components of cells, the researchers said.

“Intermittent fasting helps the body to rejuvenate and repair, thereby promoting overall health,” Panda told Live Science.

In addition, the body may respond better to meals eaten at some times of the day rather than others because of the body’s circadian rhythms. In the years before artificial light, people depended on natural patterns of day and night, with food primarily eaten during the day and fasting occurring at night. This means that eating at certain times of the day may be healthier for the body’s metabolism — for example, in 2013, two studies in humans suggested that eating meals earlier in the day improved weight loss in overweight and obese people.

Panda said that it may be challenging for people to fast intermittently, instead of eating three meals every day. Eating breakfast is often promoted as a weight-control aid, but recent evidence has suggested it might not be, the researchers said.

Future research needs to further explore the benefits and drawbacks of different types of intermittent fasting in a variety of populations. “Its effectiveness in both preventing and reversing diseases, as well as interaction with standard medications for chronic metabolic diseases, should be tested in appropriate volunteer groups,” Panda said.

http://www.livescience.com/48888-intermittent-fasting-benefits-weight-loss.html

New research shows that high salt diet suppresses weight gain in mice on a high fat diet

On By A.P.In cardiovascular disease, diet, Iowa, Iowa City, MedicineLeave a comment


Dr. Justin Grobe, PhD


Dr. Michael Lutter, MD PhD

In a study that seems to defy conventional dietary wisdom, University of Iowa scientists have found that adding high salt to a high-fat diet actually prevents weight gain in mice.

As exciting as this may sound to fast food lovers, the researchers caution that very high levels of dietary salt are associated with increased risk for cardiovascular disease in humans. Rather than suggest that a high salt diet is suddenly a good thing, the researchers say these findings really point to the profound effect non-caloric dietary nutrients can have on energy balance and weight gain.

“People focus on how much fat or sugar is in the food they eat, but [in our experiments] something that has nothing to do with caloric content – sodium – has an even bigger effect on weight gain,” say Justin Grobe, PhD, assistant professor of pharmacology at the UI Carver College of Medicine and co-senior author of the study, which was published in the journal Scientific Reports on June 11.

The UI team started the study with the hypothesis that fat and salt, both being tasty to humans, would act together to increase food consumption and promote weight gain. They tested the idea by feeding groups of mice different diets: normal chow or high-fat chow with varying levels of salt (0.25 to 4 percent). To their surprise, the mice on the high-fat diet with the lowest salt gained the most weight, about 15 grams over 16 weeks, while animals on the high-fat, highest salt diet had low weight gain that was similar to the chow-fed mice, about 5 grams.

“We found out that our ‘french fry’ hypothesis was perfectly wrong,” says Grobe, who also is a member of the Fraternal Order of Eagles Diabetes Research Center at the UI and a Fellow of the American Heart Association. “The findings also suggest that public health efforts to continue lowering sodium intake may have unexpected and unintended consequences.”

To investigate why the high salt prevented weight gain, the researchers examined four key factors that influence energy balance in animals. On the energy input side, they ruled out changes in feeding behavior – all the mice ate the same amount of calories regardless of the salt content in their diet. On the energy output side, there was no difference in resting metabolism or physical activity between the mice on different diets. In contrast, varying levels of salt had a significant effect on digestive efficiency – the amount of fat from the diet that is absorbed by the body.

“Our study shows that not all calories are created equal,” says Michael Lutter, MD, PhD, co-senior study author and UI assistant professor of psychiatry. “Our findings, in conjunction with other studies, are showing that there is a wide range of dietary efficiency, or absorption of calories, in the populations, and that may contribute to resistance or sensitivity to weight gain.”

“This suppression of weight gain with increased sodium was due entirely to a reduced efficiency of the digestive tract to extract calories from the food that was consumed,” explains Grobe.

It’s possible that this finding explains the well-known digestive ill effects of certain fast foods that are high in both fat and salt, he adds.

Through his research on hypertension, Grobe knew that salt levels affect the activity of an enzyme called renin, which is a component in the renin- angiotensin system, a hormone system commonly targeted clinically to treat various cardiovascular diseases. The new study shows that angiotensin mediates the control of digestive efficiency by dietary sodium.

The clinical usefulness of reducing digestive efficiency for treating obesity has been proven by the drug orlistat, which is sold over-the-counter as Alli. The discovery that modulating the renin-angiotensin system also reduces digestive efficiency may lead to the developments of new anti-obesity treatments.

Lutter, who also is an eating disorders specialist with UI Health Care, notes that another big implication of the findings is that we are just starting to understand complex interactions between nutrients and how they affect calorie absorption, and it is important for scientists investigating the health effects of diet to analyze diets that are more complex than those currently used in animal experiments and more accurately reflect normal eating behavior.

“Most importantly, these findings support continued and nuanced discussions of public policies regarding dietary nutrient recommendations,” Grobe adds.

http://www.eurekalert.org/pub_releases/2015-06/uoih-hsp061115.php

Sitting too much may be twice as dangerous for your health as being obese.

On By A.P.In Health, Obesity1 Comment

There’s been a fast growing body of evidence in the last several years that lack of exercise – or sedentariness – is a major risk factor in health. It’s been linked to heart disease, cancer, and to an early death. And now, a new study finds that lack of exercise may actually be even more of a risk than obesity in early mortality: The researchers calculate that a sedentary lifestyle may actually confer twice the risk of death as being obese. That said, the two are both important and, luckily, closely related: So if you start getting active, you’ll probably lose a little weight along the way, which itself is a very good thing.

The new study looked at data from over 334,000 people who participated in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study. Over a period of 12 years, the participants’ height, weight, and waist circumferences were tracked, along with self-reports of activity levels, both at work and in free time. All-cause mortality (i.e., death from any cause) was the main outcome of interest.

It turned out that lack of physical activity was linked to the greatest risk of death – and the greatest reduction in death risk was in the difference between the lowest two activity groups. In other words, just moving from “inactive” to “moderately inactive” showed the largest reduction in death risk, especially for normal weight people, but true for people of all body weights. And, the authors say, just taking a brisk 20-minute walk per day can move you from one category to the other, and reduce the risk of death anywhere from 16% to 30%.

Using a statistical model, the team also calculated that being sedentary may account for double the death risk of obesity. According to their math, of the 9.2 million deaths in Europe in 2008, about 337,000 were attributable to obesity, whereas 676,000 were attributable to sedentariness.

Another takeaway from the study, however, is that waist circumference is a bigger player in mortality risk than overall body weight, which has certainly been suggested by previous studies. Belly fat seems to be disproportionately linked to chronic health issues like heart disease, stroke, diabetes, cancer, and of course, early mortality. So reducing belly fat is always a significant benefit to one’s health.

“This large study is rather complex in its details, but the take-away messages are actually both clear and simple,” says David L, Katz, Director of the Yale University Prevention Research CenterGriffin Hospital. “At any given body weight, going from inactive to active can reduce the risk of premature mortality substantially. At any given level of activity, going from overweight to a more optimal weight can do the same. We have long known that not all forms of obesity are equally hazardous, and this study reaffirms that. Losing weight if you have an excess around the middle, where it is most dangerous, exerts an influence on mortality comparable to physical activity. Losing excess weight that is not associated with a high waist circumference reduces mortality risk, but less — as we would expect.”

But perhaps the main point in all of this is that being active and being a healthy weight are inextricably linked. Though activity by itself can offer an immediate health benefit if you remain overweight, getting active also leads naturally to loss of body weight. “This study reminds that being both fit and unfat are good for health,” says Katz, “and can add both life to years, and years to life. These are not really disparate challenges, since the physical activity that leads to fitness is on the short list of priorities for avoiding fatness as well. The challenge before us now is for our culture to make it easier to get there from here.”

Earlier this month a study showed that the concept of “healthy obesity” may be very misleading, since health markers in an obese person tend to deteriorate over time. Though the current study suggests that fitness may matter more than fatness, the two are really two sides of a coin: It would be silly to become active and not lose weight — and it would be very hard to do, since the one leads to the other. But perhaps given the great benefits of exercise alone, public health campaigns should focus not just on losing weight, but on encouraging people to add just small amounts physical activity to their lives right off the bat, and to see where it goes from there.

http://www.forbes.com/sites/alicegwalton/2015/01/15/is-lack-of-exercise-worse-for-your-health-than-obesity/

Introducing the first bank of feces

On By A.P.In Brown Cross, fecal transplant, feces, Jody Troupe, OpenBiome, ScienceLeave a comment

BY Erika Engelhaupt

A new nonprofit called OpenBiome is hoping to do for fecal transplants what blood banks have done for transfusions. It’s a kind of Brown Cross.

And it’s an idea whose time has come. Recent trials testing transplants of fecal microbes from the healthy to the sick have been so promising that people are attempting dangerous do-it-yourself fecal transplants by enema, for lack of access to authorized medical procedures.

Graduate students Carolyn Edelstein and Mark B. Smith got the idea for OpenBiome after a friend had trouble getting a fecal transplant to treat an infection with Clostridium difficile. The bacterium causes dangerous, even fatal, diarrhea and in an increasing number of cases is resistant to antibiotics.

People tend to get C. difficile infections after antibiotics or chemotherapy has knocked out helpful bacteria, allowing what is normally a background player to take over. Transplants of fecal bacteria from healthy donors can help reset the microbiome, the mix of bacteria in the body, and crowd out C. difficile. A 2011 review of 317 patients treated for C. difficile found that fecal transplants cleared up infections in 92 percent of patients. And more recent research showed that taking a round of pills containing bacteria isolated from fecal matter (without the feces itself) resolved C. difficile infections in all of 32 patients treated.

There’s also interest in transplanting healthy fecal microbiomes into people with inflammatory bowel disease or even obesity. In one recent test, mice implanted with fecal microbes from thin humans stayed thin, while mice given bacteria from obese people gained weight.

But the transplants are hard to get. As Edelstein and Smith’s friend learned, the U.S. Food and Drug Administration requires lots of paperwork for the experimental therapy, and donor feces has to be screened for a host of potential pathogens.

That’s where OpenBiome steps in. The nonprofit offers hospitals fecal samples for $250 that have been prescreened to ensure they are free of pathogens and parasites. Since October, they’ve sent more than 100 samples to a dozen hospitals and clinics, according to an interview with Smith in the Chronicle of Higher Education. Edelstein, who’s studying public affairs at Princeton, and Smith, who’s studying microbiology at MIT, recruited friends and donors and negotiated permissions with the FDA to set up the organization, which houses its samples at MIT. OpenBiome is also offering to collaborate with researchers for long-term follow-up on patients’ microbiomes.

Because FDA considers feces to be a drug in the context of transplants, OpenBiome is providing stool only for treatment of C. difficile. People hoping to shift their microbiomes for other purposes are still out of luck. Until more testing and approval comes through, that leaves open the risk that some people may resort to home transplants.

Let me be very clear about this: Whipping up an enema of your friend’s stool is a terrible idea.There are excellent reasons why people normally avoid poop: It can carry pathogens and parasites that cause serious disease. Even a donor who appears perfectly healthy might be carrying around bacteria or viruses that his or her immune system or particular microbiome mix is able to deal with. Your mileage may vary.

Your genetics, your immune system, your diet and environment — all these things create the ecology of your insides, making it hard to predict what your outcome might be. What’s more, you may need to make other medically supervised changes along with the transplant. Research on microbiome links to obesity, for instance, suggests that a new “skinny” microbiome has to be accompanied by a switch to a diet lower in fat and calories, or else the new microbes will just be outcompeted.

These dangers and complicating factors are why a supply of prescreened stool is so important. The procedures need to be done under medical supervision, and when done right the results look really promising. The recently tested pill approach avoids some of the yuck factor of fecal transplants, but most transplants are done via an enema, colonoscopy or nose tube to the gut.

If you get transplant material from OpenBiome, you’ll have to submit to one of the usual transplant methods rather than a pill, but you can rest assured you’re getting high-quality stuff. Not only are the samples screened, the donors are among the best and brightest: a few young researchers and scientists from Harvard and MIT.

Introducing the first bank of feces

Thanks to Jody Troupe for bringing this to the attention of the It’s Interesting community.