9 foods you thought were healthier than they are

Many of them boast labels like low or reduced fat.

The problem with low-fat products is simple. To accommodate for the loss of flavor that comes with removing the cream or richness in a product, food manufacturers tend to add sugar. The end result is a product that may have fewer calories and less fat, but has more sugar instead.

While high-fat diets have not been implicated in weight gain, high-sugar diets have.

The authors of a review of 50 studies on diet and weight gain published in the journal Food and Nutrition Research found that, on average, the more refined carbohydrates (such as sugar) that someone ate, the more weight they tended to gain over the study period. Similarly, the researchers behind a large review of 68 studies published in the British Medical Journal found that the more sugar someone consumed, the more they weighed.

In other words, the amount of sugar in a participant's diet could be used to roughly predict their weight, the researchers found.

Read on to find out what other high-sugar, low-fat foods truly don't deserve a healthy label.

Peanut butter and jelly

The problem: PB&J is a ubiquitous lunch item among American kids — there's even a song about it — but it's actually a less-healthy alternative to sandwiches made with hummus or lean meats.

Most peanut butter contains added sugar; jelly is replete with the ingredient. Slap those ingredients between two slices of white bread and you've got a sandwich that packs 20 grams of sugar, 14 grams fat (3.5 grams saturated), and 400 calories.

How it happened: The Great Depression popularized peanut butter on bread as a cheaper-than-meat substitute for protein. When it was combined with Welch's Grapelade — one of the first iterations of jelly — in the rations of

Egg whites

The problem: For decades, we've been led to believe that eggs are bad for us because they're packed with cholesterol. Flavorless egg substitutes ranging from Egg Beaters to pre-blended cartons of egg whites packed grocery store shelves in the 1990s and early 2000s.

How it happened: As it turns out, doesn't significantly raise blood cholesterol

Bottled juices and fast-casual smoothies

The problem: Just because they pack lots of fruit, bottled smoothies and those sold at places like Jamba Juice are not necessarily healthy. But most are also incredibly high in sugar and calories. A 15-ounce bottle of Mighty Mango-flavored Naked Juice has 290 calories, 68 grams of carbs, and a whopping 57 grams of sugar. For comparison, a 16-ounce bottle of Coke has 44 grams of sugar.

How it happened: The first blender was invented in the late 1930s, and

Cereal

The problem: Bowls of sugar-laden empty carbs got swapped for protein-rich components of the "balanced breakfast." A cup of Reese's Puffs, for example, has 160 calories, 4 grams of fat (1 gram saturated), 13 grams of sugar, 29 grams of carbs and more than 3 grams of protein. hunger pangs and mood swings and leave you with low energy

How it happened: As Jaya Saxena wrote in a post for Serious Eats, "

Sports drinks

The problem: We've been wrongly convinced that we need sugar water to prepare and refuel after a hot date with the gym. In reality, exercise scientists recommend drinking water and eating or drinking 20 grams of protein, since studies suggest that it helps recondition and build muscles.

How it happened: Working out causes you to lose fluids and electrolytes like sodium and chloride. If you're dehydrated for long periods, it can put a strain on your muscles and reduce your performance. Although drinking water will solve the problem just fine, ingesting a mix electrolytes and sugar instead will do the trick slightly faster.

Orange juice

The problem: Orange juice has become a ubiquitous component of the American breakfast. But the act of juicing a fruit removes most of its fiber, the key ingredient that keeps you feeling full and satisfied until your next meal. The result: mostly just sugar and water.

How it happened: Historian Harvey Levenstein writes in his book, "Fear of Food: A History of Why We Worry about What We Eat," that biochemist Elmer McCollum, who helped discover vitamins A, B, and D and warned against vitamin-deficient diets in the 1920s, provided ample material for orange growers, whose sales at the time were sagging.

Under the Sunkist brand, the California Fruit Growers Exchange created a campaign focused on drinking orange juice to get these vitamins in an easy, tasty way.

Coconut water

The problem: We've been led to believe that this $4-a-serving beverage is a panacea for everything from post-workout dehydration to cancer.

How it happened: $400 million

"Light" ice creams

The problem: We've been led to believe that low-fat products will lead to increased overall health and weight loss. An eight-year trial involving almost 50,000 women suggested that's highly unlikely. When roughly half of the participants went on a low-fat diet, they didn't lower their risk of breast cancer, colorectal cancer, or heart disease. Plus, they didn't lose much weight, if any.

How it happened: Headlines of the 1980s and '90s were filled with missives that fat was killing us.

Granola

The problem: We associate anything crunchy and sold in bags in the health-food aisle with nature-loving hikers — people who get lots of exercise and keep their bodies lean and healthy. But granola is no health product. In fact, it's packed with sugar and calories

How it happened: The first "corporate granola," according to a 1978 Rolling Stone article, was Heartland Natural Cereal. Its roots reach back to the '60s, when Seventh-day Adventist Wayne Schlotthauer, who'd been operating the world's largest granola factory in California using a recipe his grandma had brought over from Germany, was approached by Layton Gentry. sold him the West Coast rights to the granola recipe for $18,000.