A 2014 study found that the type of fat we consume might make all the difference. Participants in the study were asked to eat 750 extra calories every day for seven weeks. Those having excess calories from saturated fats had activated cells that promoted fat storage in the belly and increased insulin resistance. However, individuals who had a high consumption of polyunsaturated fats found in fatty fish, nuts and seeds, gained less abdominal fat and were more likely to increase muscle mass instead.
“There are many eating patterns that can be used to lose weight,” says William Samuel Yancy, M.D., director of the Duke Diet and Fitness Center and associate professor of medicine at Duke University. Many have evidence behind them, whether that’s keto, Paleo, Mediterranean, vegan, or anything else. Interestingly, there’s not as much research on what works for men as there is on women, but “for men, sometimes it’s as simple as shortening the time in which you are eating to an 8- to 10-hour window a day,” says Kristin Kirkpatrick, R.D.N., consultant for Integrative and Lifestyle Medicine for the Cleveland Clinic. Even something as straightforward as not eating after 6 PM can make a big difference—one of her male clients who lost 150 pounds found that to be especially helpful, she says.
Additionally, attempts to lose weight on low-calorie diets can lead to even more lost muscle. Studies have found that regular resistance or strength training may be a better alternative than your daily runs to preserve and gain muscle — even when coupled with a low-calorie diet. Aerobic exercise is still important, just don’t make it your only form of activity.
As you reach mid-life, the pressures pile up. Just think of the typical stressors, like caring for kids and aging parents, facing financial burdens and dealing with the demands of a job. When you’re experiencing stress, your body responds by releasing the hormone cortisol. If your stress diminishes, your hormone levels return to normal, but if you’re experiencing ongoing stress from “adulting,” cortisol levels will remain high. This can set off a series of biological events that may lead to an increased appetite with more cravings and a propensity to store fat in your belly.
To jumpstart your weight loss, the biggest focus should be to develop habits that will help you build or maintain your muscle mass. "The most effective way that women over 40 can boost their metabolism is by building muscle through weight-lifting and resistance training," says Dr. Peterson (more on that to come). But nutrition and sleep habits also play a role here.
Your body has to work harder (meaning it burns more calories) digesting protein than it does fat or carbs, so Palinski-Wade recommends the strategy of upping protein intake to many of her clients, including women who are 40 and over. "Although I don’t promote very high-protein diets, increasing your protein intake from 15 percent of your total calories to 30 percent can help you boost the calories your body burns during digestion, which may just help speed weight loss."
Once you hit 40, losing weight can feel like a lost cause. Dr. Robert Kushner, director of the Center for Lifestyle Medicine at Northwestern Medicine Center in Chicago and author of “Six Factors to Fit: Weight Loss that Works for You,” told TODAY that the total amount of calories burned every day diminishes for most people with each passing decade.