Learn which foods are the most fattening, how a common spice can trim your waistline, the surprise benefits of yo-yo dieting, the truth behind liposuction and rebound fat, and the best breakfast foods for preventing hunger. Get up-to-the-minute science news from the worlds of nutrition, diet and fitness. Plus, test how much you know about food with our quiz...
Diet and fitness scoop #1: Low-carb diets are heart-safe.
Overweight people on low-carb, high-fat diets aren’t endangering their arteries, as previously thought, say researchers at Johns Hopkins University in Baltimore.
Dieters who ate as much as 40% fat (from meat, dairy products and nuts) and no more than 30% carbohydrates (from pasta, bread and fruit) for six months displayed no damaging vascular changes, at least in the short term.
They also dropped about 10 pounds in 45 days – faster than those on low-fat diets, who took 70 days to lose 10 pounds.
“If people lose weight, that’s likely to be more important for health rather than the exact makeup of the diet,” says lead investigator Kerry Stewart, Ed.D., a professor of medicine and director of clinical and research exercise physiology.
Diet and fitness scoop #2: Those potato chips really are making you fat.
Not only does it matter how much you eat - what you eat affects weight gain. In fact, daily servings of potato chips packed on more pounds than any other food, according to a huge recent study published in the New England Journal of Medicine.
It examined data on more than 120,000 people over 12-20 years. While participants put on weight during that time – an average of almost 17 pounds – some gained more, depending on foods they ate.
“Conventional wisdom often recommends ‘everything in moderation,’ with a focus only on total calories consumed – rather than the quality of what is consumed,” says lead author Dariush Mozaffarian, M.D., associate professor of epidemiology. “Our results demonstrate the types of foods and beverages strongly linked to weight gain.”
Potato products, sugar-sweetened beverages, red meats and processed meats are all food that go straight to your muffin top.
But the study also identified fat-fighting foods: People who ate daily servings of yogurt, nuts, fruits, whole grains or vegetables gained less.
“The path to eating [better] isn’t to simply count calories, but consume a more healthy diet in general,” he adds.
Diet and fitness scoop #3: Losing weight is good for bones.
When overweight or obese women lose more than 15% of their body weight, they gain significantly higher levels of vitamin D, according to a study at the Fred Hutchinson Cancer Research Center in Seattle.
The vitamin is essential for calcium absorption, bone health and other important functions. But levels may be lower in overweight people.
“Obese people may have lower vitamin D levels circulating in the blood because it’s being stored in excess fat tissue,” says lead author Caitlin Mason, Ph.D., a postdoctoral research fellow.
When fat is lost, that vitamin D is released back into the bloodstream.
Vitamin D comes from food, supplements or the skin’s reaction to sunlight. To find out how to increase your levels, read Are You Deficient in Vitamin D?
Diet and fitness scoop #4: Yo-yo dieting may be OK.
Continually dieting and backsliding may actually be healthier than never losing weight, according to a recent study on mice at Ohio University in Athens.
Mice that switched between high-fat and low-fat meals every four weeks were healthier and lived longer than mice that only ate a high-fat diet, says lead author Edward List, Ph.D., a scientist at the university’s Edison Biotechnology Institute. In fact, they lived as long as mice on a permanent low-fat diet.
“The simple act of gaining and losing weight does not seem detrimental to lifespan,” List says.
The study can’t be replicated with humans, since there are “an infinite number of ways people yo-yo diet,” List says.
But it seems likely that “even if you can’t stay lean and live a healthy lifestyle, it’s better to keep trying to lose weight than to not diet at all,” he adds.
Diet and fitness scoop #5: Spicy food helps you eat less.
Cayenne pepper is an effective appetite suppressant, according to a recent Purdue University study.
When just one-half teaspoon of the ground red pepper was added to soup, participants were less hungry and ate significantly fewer calories afterward. The effect was more pronounced in people not used to eating spicy foods, the researchers said.
The spice also increased fat-fighting metabolism and core body temperature – possibly due to capsaicin, the chemical that gives chili peppers their heat.
Taking the pepper as a supplement wasn’t as effective, notes doctoral student Mary-Jon Ludy, who devised the study.
“When ground cayenne red pepper was mixed into a meal, as opposed to being swallowed in a capsule, more fat was burned,” Ludy says.
If you’re not a spicy food fan, she recommends adding 1/4 teaspoon to meals.
“More isn’t necessarily better,” she says.
Diet and fitness scoop #6: Liposuction isn’t a permanent fat fix.
When people have liposuction, they often believe it will get rid of excess fat for good. In fact, it’s likely to return in as little as one year, according to a surprising recent study by the University of Colorado School of Medicine.
The research, published in the journal Obesity, followed people who had fat removed from their thighs. The same amount of fat returned later, though often in other areas – such as the upper abdomen, shoulders and triceps.
This happens because “the brain [apparently seeks to] keep fat mass at a constant level,” says Teri L. Hernandez, Ph.D., R.N., assistant professor of medicine and nursing.
“So when it senses the drop in total body fat mass, over a year it restores those levels to the starting point,” she tells Lifescript.
More than half a million people in the U.S. have liposuction surgery every year, according to the journal Aesthetic Plastic Surgery.
They should realize that liposuction “isn’t a weight-loss procedure,” Hernandez says. “If people seek it out for this reason, they’ll be disappointed.”
Diet and fitness scoop #7: Curb cravings with a high-protein breakfast.
Eating a healthy, protein-rich morning meal staves off hunger later in the day, a recent study at the University of Missouri found.
As many as 60% of adolescents regularly skip breakfast and then snack on unhealthy foods high in sugar and fat, notes researcher Heather Leidy, Ph.D., assistant professor of nutrition and exercise physiology. But when they ate high-protein breakfasts, they were satisfied longer and less prone to snacking.
Plus, functional magnetic resonance imaging (MRI) scans showed less activity in the area of their brains associated with motivation to eat.
While the study was limited to adolescents, “the findings would be applicable to adults,” Leidy says.
Diet and fitness scoop #8: Good bacteria help weight control.
Your gut flora might influence how easily you pack on pounds, according to a recent study published in the British Journal of Nutrition.
In research at Lund University in Sweden, rats who were given bacteria made from lactic acid – called Lactobacillus plantarum HEAL 19 – gained significantly less weight than others, even though they ate the same high-calorie food.
The beneficial bacteria appear to keep unhealthful, inflammation-causing bacteria in check, which may explain their fat-fighting power, notes Lund University food hygiene researcher Caroline Karlsson, who ran the study.
This particular bacterium isn’t used as a human food additive, but other healthful types of bacteria can be found in yogurt and probiotic supplements, as well as fermented foods such as brine olives, sauerkraut and sour pickles, Karlsson says.
Diet and fitness scoop #9: Skipping meals can be good for you.
Brief fasts could improve blood cholesterol levels and reduce the risk of coronary artery disease and diabetes, according to a study at the Intermountain Medical Center Heart Institute in Utah.
The heart researchers recorded biological reactions among participants who fasted for 24 hours, with or without water.
“The changes that occur during fasting result in a small but important reduction in adipose tissue [body fat],” says principal investigator Benjamin D. Horne, Ph.D., director of cardiovascular and genetic epidemiology at Intermountain. That’s because fat cells are used to fuel the body, he tells Lifescript.
More research is planned to determine how often or long people need to fast to gain these health benefits. A previous Intermountain study found that regular fasters – many of whom were Mormons, who are encouraged to skip two meals one day a month – had a 39% lower risk of heart disease.
Diet and fitness scoop #10: Apples are strong medicine.
A chemical in apple peels may protect against muscle weakening as you age, according to research by the University of Iowa in Iowa City.
When mice were given ursolic acid – a natural compound also found in the peels of pears, cranberries and prunes – they had less muscle atrophy as they got older, and were healthier overall.
Ursolic acid is also found in certain herbal supplements, such as Holy Basil. But more research is needed on the chemical’s potential effect on humans, says researcher Christopher Adams, M.D., Ph.D., an associate professor of endocrine metabolism.
“It would be terrific if it reduced muscle atrophy and body fat in people,” Adams says. “We’re doing more studies to try to figure this out. In the meantime, it’s a good idea to eat a balanced diet, including some fruits and vegetables every day.”
How Much Do You Know About Food?
You know that brownies taste better when they're just out of the oven and that cranberry sauce will taste bitter if you don't add enough sugar. But do you know who invented the brownie or how to select the ripest cranberries? Aside from knowing which foods you love to curl up with, how much do you really know about the history and fun facts of your favorite foods?
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