Fad diets are a dime a dozen, and many of them are attractive for the very same reasons they’re ineffective. The ice cream diet is one such plan, one that seems too good to be true — and it likely is.

A few forms of this diet exist, but none are particularly groundbreaking. So, how do they work and are they worthwhile?

The original ice cream diet is based on a book authored by Holly McCord in 2002. The premise is simple: Add ice cream to your daily routine and you’ll lose weight. But the actual diet in practice has little to do with any weight loss benefits associated with ice cream.

“This is a calorie-restricted diet,” explains dietitian Jo Bartell. “Anytime people follow a calorie-restricted diet and eat fewer calories than they burn throughout the day, or more than they ate before following the plan, they lose weight.”

The diet suggests that you can add the sweet creamy treat to your daily life and still lose weight. This isn’t because ice cream contains any magic weight loss powers, but because you’re limiting calories.

In addition to ice cream, dieters are given low fat, high fiber meal plans. They’re also told to eat more vegetables and fruit, which are all healthy suggestions.

What’s the verdict?

“There is definitely something to be said for allowing dieters a treat like ice cream every day,” says Bartell. “When people aren’t feeling deprived and getting to enjoy something they love, they will be more likely to stick to eating for weight loss.”

Clearly, there’s backfire potential. Bartell warns that by making ice cream “allowable” on a diet, you may come to think of it as a food that won’t affect your weight loss efforts.

The ice cream diet comes down to caloric restriction.

“Anyone who eats 1,200 calories per day will lose weight in the short term, because the body will be in caloric deficit,” she says. “This has to do with lack of calories and not the ice cream.”

Eating only ice cream is never healthy. And consuming large amounts of ice cream while on a calorie-restricted diet carries much more risk than does a little extra weight.

It’s unsustainable

A dramatic drop in calories can cause fluid loss, which creates the illusion of weight loss when you’re looking at the scale but doesn’t amount to much in terms of tangible change.

The weight reduction isn’t permanent and dieters will gain weight again when they return to their normal daily diets.

Bartell adds that not all foods characterized as health foods are in fact healthy, and that many “cleanse” type diets are potentially dangerous because they promote extremely low calorie intake.

It’s unhealthy

A single cup of vanilla ice cream can contain 273 calories, 31 grams of carbohydrates, 14.5 grams of fat, and 28 grams of sugar.

Even fat-free, milk-based ice cream with “no sugar added” contains at least 6 grams of milk sugar (lactose) per cup — and has no fiber.

“This frozen dessert is still high in saturated fat and sugar and should be treated as a once-in-a-while treat,” says Bartell. And while milk-based ice cream does contain calcium, so do other, healthier options, such as Greek yogurt.

Additionally, ice cream’s high calorie content leaves little room for nutrient-dense foods on a low calorie diet. This might lead to nutrient deficiencies over time.

A healthy, well-balanced diet rich in vegetables, fruits, lean proteins, and whole grains is often the healthiest way to go.

Paired with regular exercise and minimal hype, this common sense approach is likely to give you the lasting results you’re after.

Occasional treats like ice cream are okay when you eat an otherwise healthy diet, but they should never be the foundation of your daily sustenance.