WHAT WORKS

These four diets are frequently recommended by nutrition experts

Calorie-focused diets

It’s generally the first principle of dieting for weight loss: take in fewer calories. But some diets overtly stress this.

We’ve seen many variants over the years. A recent, popular example is Volumetrics, which focuses on foods with low calorie density — such as fruits, vegetables and broth-based soups — and eating them to fullness.

Low-fat diets got their start as a means of lowering calories, since high-fat foods tend to be caloriedense. But if fats are replaced with carbs, calorie intake can rise, as many low-fat dieters discovered in the 1980s and 1990s.

Weight Watchers has evolved over the years and found different ways to count calories and fat, but it’s never strayed far from this tried-and-true approach. Mobile apps have made it easier than ever to keep track, and successful calorie-focused dieters tend to be counters, measurers and trackers.

Low-carbohydrate diets

Dr. Robert C. Atkins proposed in the 1970s that dramatically driving down carbs and replacing them largely with high-protein foods would cause bodies to switch into fatburning mode. That would prompt weight loss and body composition changes that favored lean muscle over fat.

Many variations followed: the Zone Diet, Paleo diet, Sugar Busters and the South Beach diet all draw on the idea that cutting carbs is key.

An emphasis on protein and a tolerance of fats keeps many dieters from feeling hungry. And the clear identification of foods to avoid — including anything with added sugars — makes low-carb diets easier for those who don’t want to count, don’t want to feel hungry, and don’t mind skipping sugary or carb-rich foods.

Intermittent fasting

There’s nothing new to the idea that periodic fasting can lead to renewal; it’s been central to many forms of religious observance for millennia.

But researchers are finding growing evidence that the body can be “tricked” to burn more calories — and fat — by eating foods at certain times of the day or by giving the digestive system a near-total break for a couple days each week. The Fast Diet, big in the U.K., and the Warrior Diet are examples of this new-old approach.

Scientists have turned up evidence in mice that limiting eating and drinking — except for water — to a 12-to-16-hour period during mainly daylight hours could correct a metabolism overwhelmed by 24/7 eating and aid in weight management. Now the idea is being tested in humans. It may not help people working graveyard shifts, but for dieters who would rather skimp on when they eat than what or how much, it might be just the thing.

Mediterranean diet

This really did start as a way of life. For eons, peoples living along the Mediterranean mostly ate foods that came from plants and the sea. Fresh fruits and vegetables, legumes and nuts were the backbone, often drenched in olive oil. Fish was a near-daily staple, washed down by a glass or so of red wine. Grains were whole, dairy and poultry were used sparingly, and red meat and sweets were almost absent.

Research quickly established that these eaters had low rates of cardiovascular or metabolic disease. A landmark 2013 clinical trial confirmed that for people in middle age or older, following elements of a Mediterranean diet drove down heart attacks and strokes in those with diabetes, obesity or other risk factors.

Though its principles could easily be adapted to weight loss, the Mediterranean diet isn’t designed for this. But it is powerful at protecting and enhancing health, and may mitigate some of the effects of extra weight. Given the difficulties of reversing established obesity, this way of eating is a no-brainer.