Forget high-protein diets. Here is the real key to long-term weight control.

Carbohydrates have a bad reputation among weight watchers. People proclaim that excess pounds melt away when carbs are eliminated from their diets and their plates are filled with protein instead.

Problem: The trendy high-protein/ultra-low-carb diets generally are too monotonous and extreme to be successful long-term eating plans — so although it initially appears that weight is lost with little effort, for many people the pounds soon pile back on. Also, by limiting carbohydrates, you deprive yourself of the many nutrients that these foods provide… and you miss out on the ways in which carbohydrates promote permanent weight control.

Solution: Choose the right kinds of carbohydrates — and strike a healthful balance overall among carbs, proteins and fats.

What you need to know…

JUST WHAT ARE CARBS?

Carbohydrates are plant-based compounds composed of carbon, hydrogen and oxygen that provide energy to cells. Different types…

Simple carbohydrates contain one or two sugar units per molecule. They include fructose and glucose, found in fruits… galactose, found in milk products… and sucrose (table sugar).

Complex carbohydrates consist of long chains of many sugar molecules. The most healthful type is dietary fiber — sugars linked by bonds that are not broken down by digestive enzymes. Sources of fiber include whole grains, vegetables, legumes, nuts and seeds.

Refined carbohydrates are complex carbs that have been processed and turned into simple carbs — which causes them to lose much of their fiber and nutrient content while retaining their calories.

Example: The process of refining whole wheat removes the nutrient-rich inner portion (the germ) and high-fiber coating (the bran), leaving only the soft, white, nutrient-poor endosperm from which white flour is made.

“BAD” CARBS

Just as there are “bad fats” (trans fats and saturated fats) and “good fats” (such as omega-3 fatty acids), so too are there carbs that contribute to health risks and carbs that are beneficial.

Simple and refined carbohydrates fall into the risky category. They are digested quickly, causing a rapid spike in blood glucose (sugar) levels. In response, your pancreas pumps out a lot of insulin, a hormone that ushers sugar into your cells for use as energy, thereby causing blood sugar levels to plummet. This rapid drop in blood sugar sends a signal to your brain — “Eat!” This is why consuming simple or refined carbs feels satisfying at first, but after just a little while hunger pangs return.

Concern: In general, Americans get far too many of their daily calories from simple and/or refined carbs — especially­ from cakes and other sweet baked goods… ready-to-eat sugary cereals… soft drinks… table sugar, syrups and jam… white potatoes… and white bread. No wonder so many people are overweight.

If you feel hungry all the time, it may be that you’re never entirely satisfied by what you’re eating.

Reason: Your body is designed to break down intact, whole foods. When you eat mostly refined carbs, it’s as if your brain were telling your body, “The bran is already off this rice, so there’s nothing left to do but let it come on in and add to the blood sugar.”

Example: Dieters often snack on pretzels because they are low-fat… but most pretzels are made from white flour, so when you eat them, you’re hungry again a half hour later.

Along with contributing to hunger and weight-control problems, excess consumption of refined carbohydrates may further increase the likelihood of developing diabetes among people already at risk for the disease. It also raises levels of triglycerides (a type of blood fat) and reduces HDL (“good”) cholesterol, increasing the risk for cardiovascular problems.

Recommended: Get no more than 10% to 15% of your daily calories from simple and/or refined carbs.

“GOOD” CARBS

Unlike simple carbs, complex carbohydrates are digested slowly. Blood sugar and insulin levels rise gradually and peak at lower levels. With such stability, the brain receives sustained signals of satiety — so hunger pangs and food cravings are held at bay longer.

Also: Complex carbs generally are high in vitamins, fiber and other nutrients that guard against heart disease and digestive problems… and some studies suggest that they can help reduce diabetes risk.

The glycemic index (GI), a ranking system from zero to 100, is one way to gauge the effect of various foods on blood sugar. The lower a food’s GI number, the more time your body spends breaking down and digesting it… the more stable blood sugar levels remain… and the longer you feel full.

Simple strategy: Opt for low-GI foods as much as possible. To learn the GI of various foods, visit www.glycemicindex.com and click on “GI database.”

CARB RECIPES REVISED

Small changes turn simple and/or low-carb foods into nutritious sources of complex carbohydrates that promote easy weight control. How to make over…

Burgers. Use whole-wheat buns… add minced mushrooms, onions and walnuts to the ground beef.

Burritos. Choose whole-grain corn tortillas instead of white-flour shells… add diced peppers, onions and tomatoes.

French toast. Use whole-grain bread instead of white… top with puréed fresh berries instead of syrup.

Grilled cheese. Spread whole-wheat bread with grainy mustard… top with tomato or zucchini slices… use half your usual amount of cheese… broil until cheese melts.

Lasagna. Select whole-wheat noodles… add shredded carrots and diced eggplant to the filling.

Peanut butter and jelly. Opt for whole-grain bread and natural peanut butter… instead of sugary jelly, add thin slices of apple or pineapple.

Side-dish grains. In place of white rice, cook millet, barley, bulgur or cracked wheat… stir in nuts, seeds, dried fruits and/or spices.