Restricting eating to eight-to-12 hours in a day could help ward off high cholesterol, diabetes and obesity, a U.S. study in mice suggests. The problem has arisen among children and adults who eat more as they spend more time in artificial light, as well as watching television, and interacting with tablets and smartphones. The researchers subjected 400 normal and obese mice to various diets and restrictions on eating times. The benefits of time-restricted feeding were evident regardless of the weight of the mice, type of diet or length of the time restriction. Even when their diets were high in fat, fat and sucrose or just fructose, time-restricted mice gained less weight than their unrestricted counterparts.

Vitamin D deficiency has been linked with a host of health issues, but a new study finds a link with certain mental health problems, too. U.S. and Australian researchers reviewed more than 100 scientific articles, finding an association between vitamin D deficiency and seasonal depression, sometimes called seasonal affective disorder (SAD). People with SAD show the same symptoms year after year, beginning in the fall and continuing through winter. The researchers are convinced by their findings that reduced sunlight – which produces vitamin D in the body – during the winter months probably contributes to SAD. Low vitamin D levels reduce the brain chemicals serotonin and dopamine, which are linked to depression.

In a mouse study, Japanese researchers discovered that a compound present in a flowering plant used in Chinese medicine may inhibit development of metabolic disorders associated with obesity, diabetes and fatty liver disease. Iisoliquiritigenin from the plant glycyrrhiza uralensis (Gan Cao) did a good job of inhibiting production of a high-fat, diet-induced inflammation factor (IL-1beta) in fat tissue, compared with other inflammation inhibitors, in one of the groups of mice. The researchers said that their findings could lead to development of a new herbal medication for obesity-related diseases.

Researchers in Missouri have found compelling evidence in a review of scientific studies that eating the right kinds of fatty fish can prevent development of the type of tumors found in breast, prostate, pancreas, colon and other gastrointestinal cancers. Omega-3s in fatty fish seem to work the same way as low-dose aspirin: by inhibiting the activity of the cox-2 enzyme, a major contributor to adenocarcinomas. The researchers noted that olive oil used in Italy in cooking and as a salad dressing is low in omega-6; omega-3-rich fish is a staple in the Italian diet. A high ratio of omega-3s to omega-6s is the key. Subjects in Italian studies who consumed fish at least twice weekly were at a significantly lower risk for a number of gastrointestinal cancers.

Weight-stable, physically active adolescents who consume moderate amounts of sugary drinks every day need not worry about adverse metabolic impact, a new U.S. study has found. Researchers measured insulin sensitivity and cholesterol levels of participants (boys and girls 15 to 20 years old) after they had consumed a couple of cans of either high-glucose or high-fructose beverages daily for two weeks. The researchers found that as long as the kids stayed active, there was little adverse impact from drinking the sugary beverages.

Weight loss can only happen on a balanced diet that features plenty of fruits and vegetables, as well as complex carbohydrates like bread. Some breads are better for weight loss, however, than others. The eight breads that help dieters shed pounds are: oat bread, whole wheat, brown rice bread, whole wheat pita, flaxseed, rye bread, Ezekiel bread, and gluten-free. A physician commenter on the article, however, said only Ezekiel bread (barley, wheat, lentils, beans, spelt and millet) and genuine sourdough should be eaten by dieters. The other varieties of whole grain breads raise blood sugar levels significantly, prompt insulin release contributing to pre-diabetes, and should be avoided when trying to lose weight.

The key finding of a recent U.S. study should be good news for potato lovers on a diet: eating potatoes does not prevent weight loss. In addition, potatoes are a very healthful vegetable. One medium-size (5.3 ounce) skin-on spud contains just 110 calories, has 620 mg of potassium (more than a banana), provides 45 percent of the daily requirement of vitamin C, and contains no fat, sodium or cholesterol. For the study, 90 people were divided into three groups that ate 5 to 7 servings of potatoes a week as part of a lower calorie/high GI diet, or a lower calorie/low GI diet or an unrestricted diet. After 12 weeks, all three groups had lost weight.

A new study on the impact of diet sodas on gut microbes contributes more insights -- and probably more confusion – to the debate over whether diet drinks are good or bad for health. Some research suggests that diet drinks do help people cut calories and ward off weight gain. But the new study says diet sodas alter intestinal microbiota in such a way that the risk of metabolic disease, including type 2 diabetes, increases. Skeptics warn that one study among seven people does not provide enough scientific evidence. So, as the debate rages on, everyone agrees that more, and larger, studies are needed to settle the issue.

Euromonitor summarizes the pros and cons of eating sugar in a new study that tries to put the debate in context as the amount of scientific research linking sugar to obesity increases. Among the cons that contribute to sugar’s “demonization”: refined sugar is addictive; causes tooth decay; has no nutritional value; and has been linked to obesity, insulin resistance, type 2 diabetes and heart disease. On the other hand, the sugar industry says that sugar alone cannot be blamed for obesity because saturated fats, carbohydrates and sedentary lifestyles also play a role. And sugar makes processed foods more palatable by providing texture and acting as a preservative.

The human brain chooses one food over another because of its caloric content, the higher the better, according to a Canadian study. Researchers based their conclusions on brains scans and other factors of healthy participants who were asked to look at pictures of different foods and then rate them. They also estimated caloric content. Though they weren’t able to accurately guess calories, the foods they said they would like to eat tended to be the highest calorie ones. “We found that brain activity tracked the true caloric content of foods,” the researchers said, noting that understanding why people choose certain foods could help control the factors that lead to obesity.

A U.S. study in mice fed a high-fat diet has determined that drinking clarified, pulp-free grapefruit juice reduced weight gain by 18 percent, but the researchers were not able to identify what compound in the juice was responsible. The findings revive interest in a fad diet that was purportedly debunked by earlier studies. The researchers gave one group of mice on a high-fat diet a bioactive compound (naringen) in grapefruit juice identified as a key agent in weight loss, and another group a glucose-lowering drug. The high-fat-diet mice that received naringin had lower blood glucose levels than the control group, but there was no effect on weight, suggesting that some other ingredient in grapefruit juice is also beneficial.

A study by Israeli researchers finds that a daily 100 ml dose of a new non-caffeinated beverage called “WakeUp Post Lunch Waker” helps suppress after-lunch fatigue much more effectively than caffeinated drinks. Both the WakeUp drink and caffeine beverages relieved after-lunch fatigue up to a half hour after lunch. But two hours after lunch performance dropped among participants who drank the caffeine drink. Those who drank WakeUp continued to show a significant benefit. A recent U.S. study showed that loss of productive time from fatigue and exhaustion at work cost more than $135 billion.

Compared to families eligible for, but not participating in the federal Supplemental Nutrition Assistance Program (SNAP), those in the program tend to eat less nutritious food, a U.S. study finds. In 2013, about 48 million Americans participated in SNAP, once known as the food stamp program, which helps low-income households buy groceries. The study found that SNAP participants had lower dietary quality scores overall than nonparticipating low-income people, and lower scores for fruits and vegetables, seafood and plant proteins. They also consumed more empty calories.

A U.S. study comparing the sweetness of non-nutritive sweeteners to sugar found that the sweeteners weren’t necessarily more intensely sweet. Participants in the study said they could detect sweetness at lower concentrations in such sugar substitutes as aspartame, acesulfamek and stevia, but the intensity wasn’t sweeter. The researchers said the  assumption that sweeteners are excessively sweet could be because people confuse potency – the lowest concentration that activates taste receptors – and intensity, which is the magnitude of the taste response. Sugar is actually less potent, but is more intensely sweet.

A three-month Swedish clinical study involving 38 overweight women found that taking an extract of spinach containing leaf membranes (thylakoids) reduced food cravings and increased weight loss. The control group that took a placebo lost an average of 3.5 kg while the group that was given five grams of thylakoids daily lost 5 kg. The thylakoid group also found that it was easier to stick to three meals a day, and did not experience any cravings. The researchers said taking thylakoids reinforced the body's production of satiety hormones and suppressed food cravings, leading to better appetite control, healthier eating habits and increased weight loss.

A U.S. meta-study comparing research data on the effectiveness of low-fat and low-carb diets found little weight loss difference. Any diet plan can work as long as people stick to it. The researchers analyzed data from 50 clinical trials involving 7,300 people. All diet routines were superior to no diet at six months. Compared with no diet, low-carb diets had a median difference in weight loss of 19.2 lbs., low-fat diets 17.6 lbs. Weight loss differences between individual diets were minimal. Those on the Atkins diet (low carb) lost 3.8 lbs. more than those on the Zone diet (low fat) at six months, a statistically insignificant difference.

A study by Czech scientists finds that drinking wine does benefit the cardiovascular system, but only if it is accompanied by exercise. Earlier studies have provided evidence that wine increases levels of good cholesterol, but this study is the first long-term clinical trial – 146 people with cardiovascular risk were tracked as they drank red or white wine for a year -- comparing the effects of the wine on markers of atherosclerosis. The conclusion was that both red and white wine lowered cholesterol, but only among participants who also exercised.

British researchers found significant discrepancies between lists of vitamin D-fortified foods and vitamin D data gathered from industry Web sites, trade associations and manufacturers and government vitamin D databanks. They compared 289 foods fortified with vitamin D catalogued by the UK National Diet and Nutrition Survey (NDNS) Nutrient Databank in 2008 and 2010 to the data they compiled. They concluded that the U.K. should update vitamin D food and supplement content estimations because they underestimate population intake levels of the vitamin by about three percent.

The U.S. FDA has issued an alert warning people on gluten-free diets to avoid an increasingly popular food ingredient known as lupin. A legume from the same plant family as peanuts, lupin is used as a replacement for wheat in an increasing number of gluten-free products. Food manufacturers are required to list lupin on the food label. The FDA is urging consumers with peanut and soybean allergies to read labels because of the risk of allergic reactions. Symptoms include hives, swelling of the lips, vomiting, breathing difficulties and anaphylactic shock. Even people without allergies to legume products should be aware of the ingredient.

A small company has developed a drinking cup packed with sophisticated sensors that can detect the level of certain nutrients in beverages, and then report the calorie content. Vessyl, designed to be used at home or work, displays the type of beverage poured into the cup (i.e., coffee, beer, etc.), the calorie count, and other details, like protein and sugar content. The idea, according to Mark One CEO Justin Lee, is to keep you aware of what you’re ingesting. "If you track what you consume, the likelihood of you achieving your health goal is much higher." A promotional version of Vessyl is available at $99 until next year, when the price will more than double.

Lifestyle factors may be more important for brain health than specific food ingredients, a U.S. study has found. The data indicated that people who ate baked or broiled fish at least once a week had greater grey matter brain volumes in areas of the brain responsible for memory (4.3 percent) and cognition (14 percent) and were more likely to have a college education than those who didn't eat fish regularly. Whether the fish was rich in omega 3 fatty acids didn't seem to matter. The researchers concluded that they may have tapped into a general set of lifestyle factors affecting brain health, only one of which is diet.

Researchers in Australia report that resistant starches – e.g., slightly green bananas, cooked and cooled potatoes, whole grains, beans, chickpeas, lentils, etc. – reduce the risk of colorectal cancer in people whose diet is rich in red meat. Participants in the study ate 300 g of lean red meat a day for four weeks. Levels of certain genetic molecules increased by 30 percent along with an increase in cell proliferation. For another four weeks they ate 40 g of butyrated resistant starch each day with the red meat. Levels of the molecules returned to normal. Resistant starches are not digested in the stomach and small intestine, but pass through to the colon where they act like fiber.

As insurance companies consider covering commercial diet plans and weight loss drugs, U.S. researchers who studied three of each found that some are more cost-effective than others. The Weight Watchers plan and the drug Qsymia offer the most weight loss bang for the buck. People on the Jenny Craig program lost the most weight, but Jenny Craig was the most expensive of the plans tested. Other programs/pills that met the criteria for inclusion in the analysis were Vtrim, and the drugs Lorcaserin and Orlistat. Weight Watchers is the cheapest intervention, costing an average of $377 a year. Jenny Craig cost more than $2,500. Annual costs for the diet pills are $1,743 for Lorcaserin; $1,518 for Orlistat; and $1,336 for Qsymia.

New U.S. research based on data from a national survey on health confirms again that a sedentary lifestyle – not just eating behaviors – is a significant contributor to the obesity problem in this country. The research shows a major decline in physical activity and a sharp increase in body mass index (BMI) over the last two decades. The number of U.S. adult women who said they did not exercise jumped from 19.1 percent in 1994 to 51.7 percent in 2010. The number of men who did not exercise went from 11.4 percent in 1994 to 43.5 percent. By 2010, BMI had increased among both men and women, most dramatically among women aged 18-39. Though the obesity rate rose continuously over those 20 years, total daily intake of calories, fat, carbohydrates, and protein did not change significantly.

A new wellness program that focuses more on the mental side of weight loss has gained the approval of scientists at the University of Missouri. This “non-diet” intuitive eating method involves paying attention to internal cues, such as hunger and fullness, rather than external cues, such as calorie counting and weight scales. In their testing of the “Eat for Life” approach, which focuses on mindfulness and intuitive eating as a lifestyle, participants improved their view of their bodies, and decreased eating behaviors – e.g., binging, purging and fasting – that often led to regaining weight lost in traditional diet programs.

New research on non-human primates suggests that weight management programs focusing too much on calorie intake ignore the complex interaction of carbs, fats and proteins that is so important to appetite regulation and energy intake. Primates – whether spider monkeys, orangutans or humans – “prioritize protein” over carbohydrates and fat. If we eat too little protein, we compensate by eating too much fat and carbs. According to Australian nutritional ecologist David Raubenheimer, obesity in the West has soared over the past 60 years because the proportion of protein in our diet has dropped considerably. Which, he says, is probably why high-protein diets like Atkins have been shown to aid weight loss.

People who think of their exercise activities as fun rather than a workout are less likely to chow down on calorie-packed snacks and desserts, two U.S. studies have found. In both studies, participants walked around a lake. In the first, some were told it was an exercise walk, others that it was just a scenic walk. At the subsequent lunch, those who thought they’d been exercising ate 35 percent more chocolate pudding than those on the scenic walk. The second study had the same result: those who thought they were exercising ate 124 percent more calories worth of M&Ms than the scenic – “fun” – walkers.

Reduced blood flow to leg arteries – called peripheral artery disease or PAD – can make it painful for people to walk. A new clinical study in Italy suggests that eating dark chocolate might provide some relief from the pain, cramping and fatigue associated with PAD. Twenty patients aged 60 to 78 walked on a treadmill in the morning and later after eating 40 grams of dark and milk chocolate on separate days. Participants increased their ability to walk unassisted after eating dark chocolate (85 percent cocoa content and rich in polyphenols), compared to eating milk chocolate. The authors suggested that the polyphenols in the dark chocolate reduced oxidative stress and improved blood flow in the leg arteries.

Researchers at the USDA say that orange honeydew and cantaloupe melons are both rich in beta-carotene, the precursor compound of vitamin A, which is involved in immune function, vision, reproduction, and cellular communication. People in many parts of the world are deficient in vitamin A and lack access to supplements. The researchers said the beta-carotene found in orange-fleshed honeydews and cantaloupes provides a solution to vitamin A deficiency , because it is as readily bioavailable as the beta-carotene found in carrots.