Like wolves in sheeps’ clothing, many foods with healthy reputations are actually pretty crappy for you.

While some are just plain junky, the problem with others comes down to portion size or unhealthy additions, says Joy Dubost, PhD, a registered dietician and food scientist. Eating too much of almost any food can be unhealthy. And if you mistakenly believe something’s good for you, it’s easy to overindulge, Dubost says.

Whether food marketers or outdated science is to blame, you need to watch out for each of the items on this list.

Chips, cookies and other snack foods often come packaged in low-fat, low-calorie pouches or packs. But that doesn’t mean they’re good for you, says registered dietician Alexandra Caspero. “These snack packs offer you pretty much nothing of value nutritionally, and they won’t fill you up,” she says.

Like all nuts, peanuts contain healthy monounsaturated fats, which studies have linked to lower rates of heart disease. Cut out the fat, and you’re cutting out a lot of what makes peanut butter healthy and filling. When it comes to reduced-fat PB, the fat is often replaced with sugar and unhealthy additives, says registered dietician Manuel Villacorta.

You’ve caught onto the fact that “diet” and low-cal soft drinks are bad news. But while they’re a lot healthier for you than soda, coconut water—and cactus water, and maple water, and all the other new “waters”—do contain calories, Dubost says. While they can be great for re-hydrating after a workout, sipping them throughout the day can add hundreds of calories to your diet. The only drink you can slurp without concern is H2O.

The last decade has seen waves of new research on the health benefits of coffee. Even if you’re swallowing 24 to 32 ounces a day, studies suggest your heart and brain will benefit (so long as your habit doesn’t mess with your sleep). Coffee consumption has even been linked to lower rates of skin cancer. But there’s one big caveat: All of these studies are talking about plain java without sugar or cream. If you’re adding anything to your morning joe—and especially if you’re fond of mocha frappuccinos or specialty lattes—you’re not doing your health or your waistline any favors.

Everybody loves FroYo, and for years this treat enjoyed a “healthier than ice cream” tag because of its low fat content. But it’s still a dessert, and is often loaded with even more sugar than fattier frozen treats, Dubost says. Also, since some types of dietary fats help you feel full faster, it may be easier to overdo it when it comes to frozen yogurt.

It doesn’t matter if it’s “100% juice” or “all-natural.” Fruit contains loads of fructose, or fruit sugar. And while whole fruits have plenty of digestion-supporting fiber, that fiber is absent when you sip a fruit’s juices. As a result, sugar floods your liver and gastrointestinal tract while having little to no effect on how full you feel, shows research from Louisiana State University. Blending whole fruits into smoothies is a good way to get your daily produce servings. But slugging orange juice or apple juice is a different story, the research suggests.

Whole grains are good for you. Refined grains are not. Research is clear on this. Whether you’re buying bread, cereal or bagels, healthy sounding terms like “multi-grain” or “seven-grain” are NOT the same thing as “whole grain.” Unlike healthy whole grains, refined grains (even seven of them) don’t provide much nutrient value, Dubost says.

While widely considered a health food, many of the granola products at your grocery store are packed with sugar and unhealthy oils, Dubost says. If you’re putting a spoonful on Greek yogurt, knock yourself out. But if you think a big bowl of granola is a healthy breakfast option, you’re mistaken.

Sugar is not a health food. And while there may be ecological benefits to buying unprocessed, pure forms of the sweet stuff from sugar cane or honey, as opposed to synthetic types of sugar, research shows natural sugars are still bad for your heart and waistline.

This one is a little controversial. But compared to people who eat full-fat dairy, those who stick to low- and no-fat dairy may be more likely to become obese, shows a large review study from the European Journal of Nutrition. The review’s authors say dairy fat is one of the most complex foods people consume. By stripping it away, low- and no-fat dairy products may be less satiating and more likely to promote the creation and storage of body fat. That doesn’t mean you should go nuts eating full-fat dairy. Instead, recognize that low-fat dairy—even skim milk and zero-fat yogurt—aren’t guilt-free foods.