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.
If you eat healthy and exercise regularly and still can’t lose weight, your thyroid might not be working like it should. This happens in about 5% of people, and it's most common in women and people over 60. In addition to weight gain, it can also cause fatigue, joint or muscle pain, and depression. Medications can help, so get it checked if you think it might be an issue.
If you are taking the appropriate measures (e.g., eating enough of a calorie deficit for your age and body composition, stressing less, and working on strength training) and still not losing weight, and you also have other symptoms of hypothyroidism (such as constipation, fatigue, dry hair and nails), then it may be worth considering getting your thyroid levels checked," advises Dr. Peterson.
Guys often wonder whether a dip in testosterone is at the root of their weight gain, says Dr. Stanford. "When men develop overweight and obesity, they tend to have a drop in testosterone that leads to a drop in energy and more retention of adipose tissue,” she says. The excess adipose tissue drives testosterone down. But taking testosterone isn’t usually the answer. “That’s not the underlying problem. Once we normalize the weight, the testosterone normalizes," she explains.
As we age, we tend to become more insulin resistant which can put us at risk for type 2 diabetes. When you eat foods that break down into sugar, the pancreas pumps out insulin to escort the sugar out of your blood. People with Insulin resistance don’t use insulin effectively so that cells have trouble absorbing sugar which causes a buildup of sugar and insulin in the blood. Researchers still aren’t 100% in agreement as to why, but at the end of the day, people with insulin resistance gain weight, particularly around the middle. And some research shows that lack of estrogen may cause insulin resistance.