How do I switch to a plant-based diet?

DEAR DOCTOR K:

I’m trying to shift to a more plant-based diet and have added more fruits and vegetables to my meals and snacks. What’s the next step?

DEAR READER:

Congratulations! You’ve already made some healthy changes to your diet. Evidence continues to mount that a plant-based diet — rich in fruits, vegetables, whole grains and healthy plant oils — may help reduce the risk of many health concerns, including heart disease, stroke, diabetes and cancer.

Adding fresh fruits and vegetables, as you’ve done, is a great first step. The next step is to incorporate more nuts, seeds and legumes into your meals and snacks.

These days, all sorts of nuts, from almonds and hazelnuts to walnuts and pistachios, are readily available. You can also find seeds, including pumpkin, sunflower, flax and chia seeds, in most grocery stores.

Legumes include the spectrum of beans: black, soybean, navy, lima, chickpea (garbanzo), red, great northern, pinto, fava and kidney. Peas and lentils are legumes, as are peanuts.

Nuts and seeds provide healthy mono- and polyunsaturated plant oils as well as protein. Legumes are filling and also contain lean protein. All of these foods are packed with vitamins and minerals.

These foods are chock-full of nutrients: “good” fats and carbs, protein, vitamins and antioxidants. Still, all food contains calories, even healthy food. So portion control is key. For example, nuts and seeds are rich in vegetable oils, which pack nine calories per gram. Just a handful of nuts contains 160 to 190 calories and 3 to 7 grams of protein.

Legumes generally contain more carbohydrates than nuts and seeds, but a roughly similar amount of protein per serving. A half-cup serving of cooked beans contains 115 to 125 calories and 7 to 9 grams of protein.

Try not to obsess over exact portions. A loose handful of nuts can be a healthy “dose” on your morning cereal, yogurt or oatmeal. So can a heaping tablespoon of sunflower or chia seeds. A handful of cooked beans on a salad is also a healthy meal-enhancer. That’s my lunch, nearly every day.

Add nuts, seeds and legumes to your diet gradually. Start by incorporating them into foods you already enjoy.

To get the full benefit of a plant-based diet, substitute plant-based proteins for some of your usual intake of red and processed meat. For example, substitute kidney beans for half the meat next time you make tacos. Sprinkle pumpkin seeds on your salad in place of shredded cheese. Or eat an almond butter sandwich for lunch instead of the usual ham and Swiss.

Why is a plant-based diet so healthy? Because that’s been the main diet of human beings throughout our existence. Our bodies evolved to expect such a diet. Meat meals were not common fare. And foods with refined carbohydrates and unhealthy fats (like trans fats) were virtually non-existent. The diets we’ve developed in the past two centuries, in developed nations, are not what we were built to eat — and are not good for our health.