Summer's here. Days are longer, the sun is brighter and swimsuit dread is palpable. When watching your butt flow down your leg like cottage cheese in a windsock, it's no wonder fad diets start to look good.

The fad diet has been around for many years, but interestingly enough, there are three that keep coming back. Why, you might ask? 2 reasons: 1) They kinda work a little and 2) They’ve yet to figure out a way to market eating less and exercising more.

And the 3 fad diets that won't go away are:

The Hollywood Diet(MiniFast)
This one's really popular lately. Chug the contents of their prepackaged drink for 48 hours and lose up to 10 pounds in one weekend! A variation exercise gurus use is a 'cleansing weekend' in which you don't eat after 10 am. If you get hungry they tell you to, and I'm not making this up, eat ice chips, but not too many.

Why it's brilliant: It's 2 days. What wouldn't you try for 2 days if it promised a beautiful body? Even if it doesn't work, which you know it won't, you're out 2 days and $20. If you really try and fail at losing weight you're out years of your life.

Why it kinda works: If you don't eat food your body starts to flush out water. With the diuretic the Hollywood diet slips in their drink and you will technically drop 10 pounds of water in one weekend.

Why it really doesn't: It's water weight. If you don't understand the difference between shedding water and shedding fat you might as well give up now.

The Low Fat Diet
This one got real popular in the 70s. The idea: Eating fat makes you fat. It makes sense in a primitive way. In fact, the message is so powerful we still buy pre-processed pseudo-food packed with high fructose corn syrup because someone stamped "Low Fat" on the label (Remember Snackwell cookies?)

Why it's brilliant: Who's going to say 'Eat more fat'? It sounds preposterous. This just seems like it should be true.

Why it kinda works: Fat is 9 calories per gram while carbs and protein are closer to 4. Doing nothing but reducing your fat intake and replacing it with an equal amount of something else will reduce your calorie intake.

Why it really doesn't: Because you don't replace it with an equal amount. You replace it with more - more of anything stamped 'Low Fat'. Frozen yogurt has almost as many calories as "Ben and Jerry's", but how many of us think "I'm so proud of myself for not eating ice cream?"

The Low Carb Diet
Atkins, South Beach and other imitators went the opposite direction. It's not that fat makes you fat, that's stupid. It's the sugar, the carbs. They cause your blood sugar to spike which just makes you hungry again in 15 minutes, forcing you to eat more food, but if you eat fat, well, that fills you up.

Why it's brilliant: It's not my fault that I didn't lose weight on the low fat diet, I was eating the wrong things. It has nothing to do with the fact that I was stuffing my face more than ever. If I stuff my face with what this guy says, then I'll lose weight.

Why it kinda works: Anyone who's done Atkins will tell you they lost weight - more than most of us had seen before.

Why it really doesn't: Can you honestly imagine spending the rest of your life without bread? Think about it. Carbs are a major staple of eating on every single continent, in every single country and within every single culture on the planet. You just can't get away from them. Doing Atkins is like trying to kick heroin if everywhere you went people put heroin next to your food, put little baskets of steaming heroin on the table before dinner and wrapped about 80% of what you eat in heroin before they gave it to you.

Fad diets don't work. Anything that makes outrageous promise is unsustainable or a bold-faced lie. Anything that cuts out whole food groups couldn't be healthy even if it did work. And anything that tells you to suck ice chips is not going to end well for your body. Do yourself a favor, no matter how sad you look in a bathing suit this summer avoid these 3 perennial fad diets.