Processed foods often have the nutrients and fiber stripped out of them. They are more likely to be absorbed into the bloodstream quickly, which leads to an insulin surge. That’s what makes you feel hungry and can lead to overeating and weight gain.

Processed foods can change your gut microbiome, too. Your microbiome is made up of the bacteria that live in your gut. Eating lots of red meat, processed food and fried food can make your gut microbiome less healthy, while eating a lot of plant-based foods and high-fiber foods like legumes and beans can make it healthier.

5 foods that can help you lose weight

A diet that’s heavy on whole foods and plants, such as the Mediterranean diet, can help you reach satiety — you feel full — while you don’t feel deprived. And it won’t slow down your metabolism, Manson said. So, it won’t sabotage your plans to lose weight or maintain a healthy weight.

You want to reach for:

  • Non-starchy vegetables. A good rule of thumb is, if it grows above ground and you can eat it raw, it’s probably non-starchy.
  • Low-fructose fruits. Berries are especially good, but Manson said most fruits are fine as long as you’re not eating excessive amounts.
  • High-fiber carbs such as whole grains, legumes, and beans.
  • Unsaturated fats like the ones found in olive oil and fish.
  • High-quality proteins like lentils, salmon and shellfish.

These standout foods can help your mental health, too. “When you have a healthy dietary pattern, it gets your hormones back in balance,” Manson said. “It has a favorable effect on mood and emotional well-being.”

Healthy eating shouldn’t make you feel deprived

If your diet tends toward less-healthy foods, you might think making this switch means making sacrifices. But Manson said that’s not the case: “When you have a healthy, high-quality diet, you should not feel deprived in terms of having the foods that you enjoy.”

In fact, it’s crucial that you don’t feel deprived by the food choices you’re making. “If you feel deprived, all kinds of things will happen to sabotage your ability to maintain a healthy weight,” she said. You might find yourself binging, or derailing your whole diet because it’s making you unhappy.

And a high-quality diet means choosing these foods most of the time. You can still find room for foods like pizza, French fries and ice cream. “If there are specific foods that don’t fall under the healthy diet umbrella, you would still be able to have those foods periodically,” she said. You just can’t have them every day, or several times a day. A treat meal on the weekends, or a small treat every day, is fine.

Exercise is critical for overall health, too

Manson said it’s important not to overlook exercise when it comes to managing your weight. “It’s really important to have a physically active lifestyle in order to maintain a healthy weight and have optimal health,” she said. Resistance exercises help you avoid the loss of lean body mass and muscle that comes with aging. And building muscle mass can boost your metabolism and help you maintain a healthy weight.

How to measure your progress

You don’t need to count calories or weigh yourself, Manson said. If you’re eating the right foods, you can count on satiety to guide you. You can track your progress by the way your clothes fit, and by measuring your waist circumference every few weeks. That’s a key marker because abdominal fat is more likely to be linked to Type 2 diabetes, heart disease and other chronic illnesses.