You’ve probably noticed that fiber has gotten its own public relations team lately. Food manufacturers will tout the benefits of their product’s fiber content if they can (and sometimes when they shouldn’t if the grams of fiber are ridiculously low). This is all for good reason, as a growing body of scientific research continues to prove the benefits of fiber for heart health, disease prevention, and weight control. Emerging research shows how fiber can lower bad (LDL) cholesterol, blood pressure, the risk for developing diabetes and some types of cancer, and help people to lose weight.

Women need to get at least 25 grams of fiber a day; men should aim for 30 grams a day. A lot of us fall far short of these targets. Some studies suggest that consuming an extra 14 grams of fiber per day (a total of 39 to 44 grams per day) may cause the body to absorb 10 percent fewer calories.

Fiber comes in two forms, soluble and insoluble, and it’s good to get a balance of both. Soluble fiber dissolves in water and is found mostly in nuts, seeds, legumes (beans, lentils, peas), fruit, and oat bran. It’s the “digestible” fiber that helps lower your risk for heart disease and can lower bad cholesterol. Insoluble fiber, on the other hand, does not dissolve in water so it’s this “indigestible” form. Found mostly in whole grains and vegetables, it passes through your body and literally acts like a broom through your system, pushing food along and aiding in digestive health.

It helps to think of fiber as a traffic cop. It allows your digestion to reach an ideal speed that supports optimal metabolism and, ultimately, fullness. Just as all foods are not created equal, not all foods get digested at the same speed. Nutrients from certain foods get in your bloodstream at different times, which changes the chemistry of hormones that either make you feel full or stimulate you to want more food. Insulin in particular, the pancreatic hormone that spikes when you’re eating carbohydrates, guides glucose from the blood to the cells. It’s largely responsible for making you feel hungry for more when you’ve eaten quickly digested foods, such as white bread and fruit juice.

Simple carbohydrates take only 5 to 10 minutes to get absorbed. Foods that make you feel full, though, take longer to get into the system, somewhere between 30 minutes to 2 hours, depending on the food’s makeup. This ideal window of 30 minutes to 2 hours happens when you eat proteins, and high-fiber veggies, fruits, and whole grains, which help prevent insulin surges and maintain a healthy blood-sugar balance.

So fiber becomes a key player in creating a meal that will get digested slowly, and as such, is less likely to be quickly converted to fat and stored. For instance, in the presence of fiber, plain old sugar will get released more gradually into the bloodstream than if it were traveling alone. In fact, you can combine a quickly digested food such as white bread with a slow one that has fiber and change the entire chemistry of a meal. Here’s an example: top a bagel or English muffin with peanut butter and a spoonful of wheat germ. The fiber in the peanut butter and wheat germ will prevent the glucose in the bagel from getting rapidly digested. It’s like the difference between foods traveling on a highway versus side roads with street lights that slow down the traffic.

Following is a list of high-fiber foods broken down into three tiers. I’ve created these separate categories because there’s a difference between eating a cup of kale versus a cup of rice, even if it’s brown rice. Choose from Tier I as often as you like; these are your all-star vegetables that will make you full on less due to their fiber and water content. Tier II includes fruits, which also have fiber and volume but a higher concentration of sugar (and thus calories). When you eat from Tier II, be sure you’re eating the whole fruit and not just the juice! Any fruits with edible skins, such as apples and berries, are great choices because the skins contain fiber too. Tier III includes the grains and starchy vegetables, which are dense in calories but have a Full effect due to their high fiber content.

TIER I (High-Volume Vegetables and Fruits):

Artichoke, arugula, asparagus, broccoli, Brussels sprouts, cauliflower, celery, chard, collard greens, cucumber, green beans, kale, mushrooms, mustard greens, onion, peas, red and green cabbage, romaine lettuce, spinach, sugar snap peas, summer squash, tomato, turnips, water chestnuts, zucchini.

TIER II (Medium to Low-Volume Vegetables and Fruits):

Apples, apricot, banana, beets, berries (especially blackberries, raspberries, blueberries), cantaloupe, carrots, cherries, dates, grapefruit, kiwi, mango, nectarine, orange, papaya, parsnips, peach, pear, pineapple, plum, prunes, pumpkin, rutabaga, sweet pepper, watermelon, winter squash.

TIER III (Grains and Starchy Vegetables):

Beans (black, pinto, kidney, garbanzo, lima), bran cereals, brown rice, butternut squash, corn, eggplant, lentils, oatmeal, potato, quinoa, split peas, sweet potato or yams, whole-grain bread, whole-grain cereals, whole-grain crackers, whole-grain tortillas, whole-wheat couscous , whole-wheat pasta.