Lost sleep can add up to extra weight, according to new research from the Mayo Clinic. In the eight-day study, healthy adults who slept 80 fewer minutes than a control group consumed an average of 549 additional calories daily. Although they were awake longer, their activity level remained stagnant and they didn't burn more calories during those extra hours. So why the spike in appetite? Researchers aren't sure. Previous studies have shown that sleep-deprived people eat more in part because the satiety hormone leptin goes down while the hunger hormone ghrelin goes up--but in this study, researchers saw a trend in the opposite direction, says Andrew D. Calvin, MD, co-investigator cardiology fellow and assistant professor of medicine at Mayo Clinic. The hormonal changes appear to be the result of the increased food consumption, not the cause. Still, Calvin stresses: "If people want to maintain a healthy weight or lose weight, they should try to avoid sleep deprivation."
If you only have time to hit the treadmill or the weight rack, go for the run, suggests a study in the American Journal of Physiology. When researchers assigned a group of overweight, sedentary adults to one of three exercise groups--aerobic training, resistance training, or a combination of both--they found that the adults who ran, cycled, rowed, or used the elliptical burned 67 percent more calories and lost 6.5 percent more total belly fat. Although the combo group spent more time exercising, they fared the same as the aerobic group. In other words, if you're strapped for time and want to torch calories, cardio gives you more bang for your buck, say researchers. Aim for at least 30 minutes of moderate-intensity exercise five days a week.
Working up a sweat first thing in the morning is great for your metabolism, but you may want to do it before breakfast, finds a 2010 study in The Journal of Physiology. Researchers recruited a group of healthy, active men, pumped up the calories and fat in their daily diets, and then split them into three groups. The first did no exercise. The second group downed a carb-heavy breakfast an hour and a half before each of four weekly strenuous running and cycling workouts. They also sipped a sports drink while exercising. The third group followed the same fitness plan as the second, but drank water while exercising and didn't eat breakfast until mid-afternoon.
After six weeks, only the third group came away unscathed--they gained no weight and burned the extra fat they were eating more efficiently. Meanwhile, both the sedentary and the pre-exercise breakfast eaters gained weight, developed insulin resistance, and began storing more fat. "Stimulation of fat metabolism very much depends on insulin and adrenaline circulating during exercise," says Peter Hespel, PhD, professor in exercise physiology at Catholic University Leuven in Belgium. Exercising in a fasted state lowers insulin and raises adrenaline, which may force muscles to burn fat, instead of carbs, for energy. Try sticking to water during your morning workouts and eating afterward.
Have you ever heard the maxim: Eat breakfast like a king, lunch like a prince, and dinner like a pauper? Well erase it from your memory--bigger isn't better, according to a 2011 study of more than 300 normal weight, overweight, and obese adults published in Nutrition Journal. (Video: Make the ultimate fat-burning breakfast) When researchers tracked the participants' dietary habits, they found that no matter how many calories people consumed in the morning, they still ate the same amount at lunch and dinner. That means a person who eats big breakfasts--on average about 400 calories more than a small breakfast--will eat more total calories daily. When it comes to making your morning meal, researchers suggest focusing quality over quantity.
Drop that bread and open the fridge: Dieters who ate a two-egg breakfast every day for two months experienced a 65 percent greater weight loss and 34 percent greater reduction in waist circumference compared to those who ate a bagel breakfast containing the same number of calories, according to a study in the International Journal of Obesity. Protein is know to be more filling than fat or carbohydrates, says study author Nikhil Dhurandhar, PhD, professor at the Pennington Biomedical Research Center in Baton Rouge, LA. "Our research suggests that better quality protein increases the levels of satiety hormone peptide YY and reduces the hunger hormone ghrelin." Round out your eggs, as the study participants did, with two slices of toast with jam.
Spicing up your food may help you drop pounds--especially if you tend to walk on the mild side, according to a 2011 study in Physiology & Behavior. When individuals who normally don't eat spicy food sprinkled a meal with half a teaspoon of ground cayenne red pepper, they experienced a decrease of hunger--in particular for fatty, salty, and sweet foods--and ate 70 fewer calories at their next meal. Participants who were regular red pepper eaters still experienced a modest up-tick in metabolism--burning about 10 extra calories--but may have been too desensitized to the heat to get the full effects, say researchers.
Search: Foods that contain capsaicin
Why do red peppers work? Much like exercise, capsaicin, the ingredient that gives chiles their kick, appears to increase activity of the body's sympathetic nervous system, says lead author Mary-Jon Lundy, PhD, RD, assistant professor of clinical nutrition at Bowling Green State University in Bowling Green, Ohio. If you want to try to slim down by heating up, add as much spice (like red pepper flakes or hot sauce) that you find pleasant--doses as small as a quarter teaspoon should work--to your morning omelet.
To defeat your muffin top, don't shy away from dairy, suggests a two-year study in the American Journal of Clinical Nutrition. When researchers tracked the dietary habits of overweight men and women, they found that participants who were consuming the most dairy daily--about 12 ounces of milk or 580 milligrams of calcium--lost about five pounds more by the end of the study than people who got the least--about half a glass of milk or 150 mg of calcium. Clinical studies show that increases in dietary calcium can help individuals to excrete more fat, says study author Danit-Rivka Shahar, RD, PhD, professor in the department of epidemiology and health evaluation at Ben-Gurion University of the Negev in Israel. When making breakfast, add some low-fat milk, cheese or yogurt to your meal.
If you must have chocolate, cookies, cake, or ice cream, consider moving your daily dessert fix to breakfast. Dieters who ate a sugary treat after a high-carbohydrate, protein-enriched breakfast lost an average of 40 pounds more than dieters who skipped dessert but consumed the same total number of calories daily, according to a new eight-month study in Steroids. Researchers believe eating a bigger breakfast helps suppress the appetite-stimulating hormone gherlin, which leads to increased satiety and fewer cravings for sweets, fats, and greasy fast food throughout the day. Go ahead and add something sweet to your breakfast--just make sure the total meal is high in healthy sources of protein and carbs and doesn't come in over 600 calories.
For a warm, waist-friendly beverage that will still put a little pep in your step, swap your java for green tea. People who regularly drink an average of two cups of caffeinated tea--mostly green--per day have lower body fat and smaller waists than those who don't, according to a 2010 meta-analysis. The antioxidants in green tea, along with the caffeine, may increase how fast fat is broken down in the body, say researchers. Brew a fresh pot daily--the antioxidants in bottled teas may not be as strong.
If you have a craving for sweets, sprinkle chocolate chips in your oatmeal or add some cocoa to your coffee, suggests a new study of healthy, active men and women. Researchers from the University of California-San Diego found that adults who eat chocolate regularly are thinner than those who don't--each additional snack session per week was associated with about a .2-point reduction in body mass index (BMI). That means if you eat chocolate five times a week you could have a one point lower BMI compared to someone who abstains. That may not sound significant, but it actually translates to a 7 fewer pounds for someone who is 5 foot 10 inches tall.
Chocolate is known to benefit blood pressure and insulin sensitivity, but it also contains epicatechin, a compound that boosts the number of blood vessels and energy-producing mitochondria in muscle, both of which may help increase muscle function and calorie burning, said lead study author Beatrice Golomb, MD, PhD, associate professor of medicine at the UC-San Diego. In the study, frequency mattered more than the portion, but if you want to keep your serving sizes in check, opt for four ounces of dark chocolate per day.
To really win the battle of the bulge, you have to stay active where you spend most of your time: at work. Obese individuals tend to be seated for 2.5 hours per day more than their lean, sedentary counterparts, according to a review in Arteriosclerosis, Thrombosis, and Vascular Biology. However, Mayo Clinic researcher James A. Levine, MD, PhD, found that people with higher levels of non-exercise activity thermogenesis (NEAT)--or non-exercise activities, such as fidgeting--can burn 350 additional calories per day. Over the course of a year, that can turn into a 36-pound weight loss. Each morning, before your day gets too busy, make it your mission to move more: stand up when you answer the phone, walk to your coworkers' desks instead of emailing, or use a mini-stepper under your desk. Employees who did the latter burned up to 335 additional calories compared to when they stayed sedentary, according to a study in the British Journal of Sports Medicine.
Protein is essential to a healthy diet, but what type you eat may impact your weight, according to a study in the European Journal of Clinical Nutrition. Researchers found that when healthy males consumed fish instead of beef for lunch, they ate 11 percent fewer calories during dinner. It's possible that the amino acid composition in fish protein increases satiety more, says study author Stephan Rössner, MD, PhD, professor emeritus at the Karolinska Institute in Sweden. Keep your lunch balanced by making sure 40 percent of your meal's calories come from the fish.
Up Next: Lose Weight While You Sleep