吃好早餐有助于减肥 （英）

Bigger Meals Earlier Can Help Weight Loss

By ANN LUKITS

Skipping breakfast and overeating in the evening have been shown to play a significant role in weight gain and obesity. A study in the journal Obesity found that consuming the heaviest meal of the day at breakfast and the lightest at dinner can lead to significant weight loss.

From June to October 2012, researchers at Tel Aviv University in Israel recruited 93 overweight and obese women to participate in a three-month, 1,400-calorie-a-day diet, an amount recommended in some weight-loss diets. The women were in their mid-40s and had metabolic syndrome, the term for a cluster of health conditions associated with Type 2 diabetes. Half the women were assigned to a breakfast group (BF) that consumed 50% of the allotted daily calories at breakfast, 36% at lunch and 14% at dinner. A dinner group (D) did the opposite, eating 14% of calories at breakfast, 36% at midday and 50% at dinner. Participants were measured for various body and metabolic markers every two weeks.

James Steinberg

The BF subjects lost an average 19.1 pounds over 12 weeks, while the D group shed 7.9 pounds. BF subjects trimmed 3.3 inches from their waistlines compared with 1.5 inches in D group; body-mass index dropped 10% and 5% in the BF and D groups, respectively.

Average triglyceride levels, an indicator of cardiovascular health, decreased by 34% in BF subjects but increased by 15% in D subjects. Total cholesterol slightly decreased in both groups but HDL levels, the so-called good cholesterol, increased significantly only in the BF group.

Levels of glucose, insulin and ghrelin, an appetite hormone, decreased significantly in both groups but to a greater extent in BF subjects. The BF group also had significantly lower glucose and insulin responses in post-lunch blood tests, suggesting that eating a relatively high-calorie breakfast helped to maintain stable insulin levels after the second meal of the day, researchers said.

Caveat: The study was too short to determine the long-term health benefits of high-energy intake at breakfast, they said.

Title: High Caloric Intake at Breakfast vs. Dinner Differentially Influences Weight Loss of Overweight and Obese Women

Infertility insights: A specialized immune system cell called a macrophage may play an essential role in a woman's ability to become pregnant and could be an important new target for infertility treatments, a study in the Journal of Clinical Investigation suggests.

Macrophages are white blood cells that attack and destroy harmful organisms that enter the body. Recent studies indicate macrophages are also present in women's reproductive tissues, though their exact role isn't clear. In the latest study, scientists found that insufficient macrophages lead to adverse effects on embryo development and reproductive failure in mice.

The study, conducted in Australia, involved experiments on a strain of mice bred to allow systemic depletion of macrophages. A control group comprised genetically normal mice. Both groups were administered diphtheria toxin (DT), which sharply depleted uterine and ovarian macrophages in the genetically altered mice compared with controls.

Removal of macrophages resulted in infertility in the genetically altered mice. These mice were found to lack healthy embryo implantation sites and to have insufficient levels of progesterone, a hormone essential to pregnancy. By comparison, the control mice had twice as many implantation sites, all of which were normal in appearance.

Fertility was largely restored in the genetically altered mice after they received injections of progesterone. Some 92% of these mice were able to carry viable pregnancies, and their embryo implantation sites were similar in size and number to those of the control mice. The study found that macrophage depletion appears to damage the corpus luteum, which is the part of the ovary responsible for secreting progesterone.

Caveat: Diphtheria toxin affects other cells that may contribute to the infertility observed in the study, researchers said. The link between insufficient macrophages and infertility hasn't been confirmed in women.

http://online.wsj.com/article/SB10001424127887323420604578649932108923480.html?mod=WSJASIA_hpp_MIDDLELSMini​​​