Carbs are essential for weight loss, according to a nutrition doctor. Here's how to choose the right kinds.

• If you want to eat well and lose weight, 75% of your plate should be carbs, says Dr. Mark Hyman.
• Carbs like green veggies and fruit should be the majority of your diet by volume, not by calories.
• These foods are nutrient-dense, in contrast to refined carbs like sugar that can be unhealthy.

Carbohydrates have a bad reputation these days amid the popularity of keto and low-carb diets. People have come to associate too many carbs with insulin resistance, weight gain, and unhealthy eating habits.

Nothing could be further than the truth, according to Dr. Mark Hyman, a family physician who specializes in a food-as-medicine approach to health, and the author of "Food Fix" and "Eat Fat, Get Thin."

"Carbs are the single most important thing you can eat for health and weight loss," Hyman told Insider in an email interview about his new book, "The Pegan Diet."

Both the quality and the quantity of carbs matter for your diet goals, he explained. Nutrient-dense, lower calorie carb sources can be a foundation of a healthy diet, helping to cut out "empty" calories like sugar and refined carbs.

Carbs should make up most of your diet by volume, not by calories

The standard American diet (SAD for short) is often criticized for fueling high rates of insulin resistance, metabolic dysfunction, and obesity. It features lots of carbs - dietary guidelines recommend that carbs make up 45-65% of daily calories, but studies show Americans often get most of that from processed foods.

"In fact, most of the SAD diet is refined carbohydrates from bread, rice, cereal, pasta, and pastries," Hyman said

It's OK to make carbs the center of your diet, Hyman said, but not by getting the bulk of your calories from those processed sources.

The key to the ideal diet, according to Hyman, is filling 75% of your plate with nutritious, non-starchy veggies like greens, mushrooms, peppers, and tomatoes.

Since these foods are lower in calories, they leave plenty of room to round out your daily energy needs with healthy fat sources like fish, olive oil, and avocado, and protein from sources like beans, grass-fed meat, and eggs.

Prioritize 'slow' carbs like nutrient-dense veggies and fruits

For a healthy diet of 75% carbs (by volume), the type of carbohydrate source matters a lot.

"A hot fudge sundae and cauliflower both fall into the carbs category, yet they are entirely different foods," Hyman said.

Aiming for carb sources like leafy greens, berries, and non-starchy vegetables allows you to get the most bang for your buck, in terms of daily energy.

That's because they come packed with nutrients like fiber, vitamins, phytonutrients, and minerals, which help promote healthy digestion and a strong microbiome (beneficial bacteria in your gut).

These "slow" carbs, as Hyman calls them, help you feel full and energized for longer after eating, while avoiding the blood sugar spikes and dips that "fast" carbs like sugar can cause.

Treat sugar and other refined carbs as occasional treats, not staples

Unlike fruit and vegetables, Hyman said, refined and processed carbohydrates should be treated like recreational drugs - consumed in limited quantities as an occasional indulgence, if at all.

Dr. Ashley Gearhardt, a food addiction researcher and psychology professor at the University of Michigan, told Insider that the combination of sugar and fat in processed foods can encourage us to eat more than we intend to.

Gearhardt said it can be sensationalist to compare addictive foods to drugs, but the risks should be taken seriously.

That can be challenging when processed food is more available than fresh ingredients, and if you don't have time to cook.

"We do all have to eat, and it's not an even playing field since these foods are engineered in a way that they're using our biology against us," Gearhardt said. "It's like having beer in the water fountains. That's our food environment."

Gearhardt's solution is to try to avoid having a lot of processed foods in the house whenever possible, and be deliberate about the choice to indulge.

"I think of them the same as red wine. It's a thoughtful process with boundaries and mindfulness," she said.