For most of my mother's life, she was able to keep to a healthy weight with little effort, but perimenopause changed that. She was surprised to see that she was gaining weight.

My mom wasn't alone in this. Weight gain during perimenopause is a concern for a lot of women. So I reached out to Dr. Barb Depree, director of the Women's Midlife Services at Holland Hospital and a member of HealthyWomen's Women's Health Advisory Council to find out how to manage this concern.

"The approach to weight maintenance in the menopause transition doesn't sound much different than other times, generally speaking," said DePree, "but the effort required is increased."

How perimenopause impacts weight gain

During perimenopause — which typically starts around age 40 — your estrogen levels start to fluctuate, so your body starts to look for an estrogen replacement and finds one in fat, which produces estrone, the weakest version of the three types of estrogen, which also include estradiol and estriol.

"Fat is a source of estrogen," DePree said. "So the body is very efficient in providing a 'replacement' . . . [The result is that] the body deposits fat very readily, especially in the midsection."

Food and nutritional supplements can't replace estradiol, the strongest of the three forms of estrogen. The only way to get it back is with hormone replacement therapy, which comes with some health risks.

DePree pointed out that losing estrogen already increases your risk of developing heart disease and Type II diabetes, and adding weight gain to that just makes your risks greater. "Entering the menopause transition, or perimenopause, at an ideal body weight is very important in reducing the likelihood of having a chronic disease in menopause."

What to eat and why

The first thing women should do is to take a look at the foods that make up their diet.

"Many factors influence how a person's body responds to different foods and dietary patterns, such as genetics, underlying health conditions, weight history, gut bacteria and more," said Emily A. Callahan, a registered dietician nutritionist and member of HealthyWomen's Women's Health Advisory Council. "That said, some research has examined how certain foods may contribute to weight gain."

A 2011 study from Harvard University confirmed what most people already knew: Starchy foods such as French fries and potatoes, refined grains, like cereal and cookies, and sugary drinks lead to increased weight gain.

"That doesn't mean that these foods have to be completely avoided, but it's a good idea to limit how often you eat them and keep portion sizes small if you do," Callahan said. "Dietary patterns that emphasize whole grains, fruits, and vegetables seem to protect against weight gain."

Callahan says it's a good idea to check out the USDA's Dietary Guidelines for Americans and the American Heart Association for suggestions on what to eat. Both emphasize plant-based foods including fruit, legumes, nuts, whole grains, plus lean protein and fish.

"One of the key messages from the Dietary Guidelines is to make half of your plate fruits and veggies, which I think is an easy visual cue that can help people reap all the benefits of these foods," Callahan said.

DePree recommends trying the Mediterranean diet, which emphasizes healthy fats like monounsaturated fat found in olive oil and omega-3 fatty acids, common in salmon.

Stay hydrated

Perimenopause and menopause also come with a surprising side effect: dehydration. One study found that changes in estrogen levels can impact women's ability to regulate fluids. It takes more time for their bodies to replenish fluids, putting them at higher risk for dehydration.

Since up to 60% of the human body is water, it's crucial to stay hydrated. Water helps regulate body temperature, keeps joints lubricated and delivers nutrients to cells, among other important functions. It also plays a role in weight gain: The energy provided by water helps the body burn fat.

"One way that water may help with weight is by reducing liquid calorie intake when water is substituted for calorie-containing beverages such as soft drinks, juice, punch, or sweetened teas and coffees," Callahan said.

"Plain water is best, but if you get tired of that, try seltzer or sparkling water without added sweeteners, or add slices of fresh fruit to your water," Callahan said.

Foods, such as fruits, vegetables and soup can also help supplement water intake.

Be wary of weight loss supplements

If you search the internet for "perimenopause weight loss," you'll get a bunch of ads for supplements, but buyer beware: Many of them may promise more than they can deliver. Callahan advises checking the National Institute of Health's Office of Dietary Supplements and the Food and Drug Administration's Dietary Supplement Ingredient Advisory List to better understand what ingredients are being used.

"The supplement industry is relatively loosely regulated and women should do their homework and talk to their health care provider before trying a supplement to support weight loss," Callahan said.

Stay active

While changing your diet can help with weight gain, it's also important to exercise.

"Diet and nutrition matter a great deal, but caloric restriction is only sustainable for so long, and can only get you so far," DePree said. "Exercise is the key to not only weight management, but cardiovascular health, improvements in mood and sleep, and bone health."

There is no one-size-fits-all exercise routine, but the Mayo Clinic recommends aerobic activity, strength training, stretching, and stability and balance exercises for women of menopausal age. The Centers for Disease Control (CDC) recommends adults up to age 64 do at least 150 minutes of moderate exercise (such as a brisk walk) per week, and two days per week of strength training. (It's always a good idea to consult your health care provider before beginning a new exercise routine.)

"[Exercising] is a big investment but well worth it when you look at paving the way ahead for the next 30 to 40 years," DePree said. "Investing in yourself is critical and finding the time and energy to prioritize for your own needs must rise in the 'to-do' list."

The secret to becoming healthier is to make changes you can live with over the long haul. You don't have to give up carbs and sugar completely and run an entire marathon. You just need to take that first step.