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Late Bedtime = Weight Gain

Simply going to bed late on weeknights can set you up for gaining weight, no matter how much you exercise, how many hours of sleep you get or how much time you spend in front of a TV or computer screen. To arrive at this conclusion, researchers at the University of California, Berkeley analyzed data including bedtimes from 3,342 young people participating in a national study of adolescent health that has been ongoing since 1994. The investigators focused on three time periods – the onset of puberty, college-age years and young adulthood. Participants reported both their bedtimes and the number of hours they slept, and the researchers calculated BMIs based on each participant’s height and weight. Losing sleep due to late bedtimes was associated with a 2.1 gain in BMI over a five-year period. The findings suggest that going to bed earlier could set teens’ weight on a healthier track as they reach adulthood, said study leader Lauren Asarnow.

Why Late Night Eating is a Bad Idea

Eating late at night when you can’t sleep can lead to problems beyond weight gain - it may compromise your concentration and alertness. Researchers from the University of Pennsylvania report that adults consume about 500 extra calories late at night when their sleep is limited. To investigate the effects of those excess calories, the researchers gave 44 adults ages 21 to 50 unrestricted access to food and drink but allowed them to sleep for only four hours a night for three nights. On the fourth night, 20 of the participants could eat and drink all they wanted, while 24 were prevented from snacking - they were allowed to drink only water from 10 p.m. until their 4 a.m. bedtime. Each night at 2 a.m. during the study all the participants took tests to evaluate their working memory, cognitive skills, sleepiness, stress levels and mood. On the fourth night, participants who drank only water after 10 p.m. performed better on tests of reaction time and attention than those who had eaten, even though both groups had the same sleep restrictions. 

Secondhand Smoke Promotes Weight Gain

As if secondhand smoke didn't do enough harm - increasing the risk of lung cancer, other respiratory diseases, heart disease and stroke - it can also make you put on fatty tissue and is particularly hard on kids. Researchers from Brigham Young University wanted to know why smokers become insulin resistant, which leads to weight gain, so they exposed mice to secondhand smoke and observed them for changes in their physiology. The mice exposed to the smoke soon began to put on weight, and further research showed that the smoke disrupted normal cell function. The mechanism appears to involve triggering a constituent of fat called ceramide, which alters the metabolism of mitochondria, inhibiting their ability to respond normally to insulin. Once you become insulin resistant, your body needs and produces more insulin to meet metabolic needs, which drives weight gain. The researchers were able to inhibit ceramide in mice with a substance called myriocin and are now trying to find a ceramide inhibitor that is safe and effective for humans.

Skirt Size and Breast Cancer Risk

If your skirt size increased between the ages of 25 and 60, your risk of breast cancer has likely increased, too, according to the results of a new British study. Researchers at University College London examined data from nearly 93,000 British women and found that three out of four reported bigger skirt sizes at the average age of 64 compared to their size at age 25. The investigators reported that for every increase in skirt size breast cancer risk jumped by 33 percent. This would mean a 77 percent increased risk for women whose skirt sizes went up two sizes size every 10 years from age 25 until after menopause. The study team determined that increases in skirt size was the strongest predictor of a breast cancer diagnosis, and noted that skirt size served as a proxy for abdominal weight gain. Bear in mind, however, that a 77 percent increased risk isn't as frightening as it sounds, since it is its based on relative risk. This is what "relative risk" means: assume that out of every 100 women one will develop breast cancer; a 77 percent increased relative risk means that 1.77 women will develop breast cancer and that 98.23 will not.

Surprising Stress Effect on Weight Gain

Stress can send you straight to the ice cream in the freezer or the pizza joint on the way home, but new research has found that the subsequent weight gain is more complex than just packing in extra calories. A study at Ohio State found that you actually burn fewer calories when eating under stress than someone who eats the exact same thing but isn’t stressed out. A group of 58 women, average age 53, participated in the study. They were provided with three standardized meals. The test meal provided 930 calories, including 60 grams of fat, and consisted of eggs, turkey sausage, biscuits and gravy, the caloric equivalent of a fast food meal of a two-patty burger and an order of fries. They were asked to fast for 12 hours before they returned to the Clinical Research Center. They then reported on any stress they had encountered in the past 24 hours. After the standardized meal, measurements of the women’s metabolic rate (how fast they burned the calories) showed that the participants who reported the most stress burned 104 fewer calories than the others. The researchers estimated that the daily effect of this pattern could add up to 11 pounds per year.

My take? We’ve long known that stress can trigger binge eating and lead to weight gain, and this study gives us a window into one of the possible mechanisms involved. The biochemical aspects linking stress and metabolism have yet to be worked out, and may eventually provide a target for intervention, but if you want to decrease the impact of stress in your life and on your weight, you should start by getting regular exercise and sufficient sleep. Incorporate meditation and relaxation techniques into your daily routine. Breathing exercises, particularly performing the 4-7-8 Breath, will help bring calmness throughout your body. Practice it at least twice a day, and try it every time you feel anxious or upset.

Janice K. Kielcolt-Glaser et al, “Daily Stressors, Past Depression, and Metabolic Responses to High-Fat Meals: A Novel Path to Obesity,” Biological Psychiatry,