OK! COVER STORY: The Secrets to Kim Kardashian's Super-Fast Slimdown

Like for so many of us, summer completely crept up on Kim Kardashian.

Suddenly she realized it was July and she still wasn't down to her perfect bikini weight. "I have majorly fallen all of my workout and eating plan! AND it's summer! Kimmmmyyyy! Starting tonight! Swear!" Kim Tweeted to her followers on July 7.

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But the 5-foot-2-inch reality star is nothing if not determined. She started a diet-and-exercise regimen and managed to carve seven pounds off her figure in just seven days to reach her goal weight of approximately 117 pounds. "If I don't feel confident about my body, I'm not going to sit at home and feel sorry for myself and not do something about it," Kim has said. "It's all about taking action and not being lazy. So you do the work, whether it’s fitness or whatever. It’s all about getting up, motivating yourself and just doing it.’’

Just doing it, indeed. Hello, boyfriend Kanye West! “We jokingly refer to it as the sex diet,” says a family source. “When one of us is having regular sex, that tends to burn calories and kill the appetite. Losing seven pounds in seven days means being a very naughty girl!”

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To drop weight fast, Kim streamlined her diet by cutting out all gluten, sugar and dairy. “Kim is a sugar addict, so cutting it out was really hard, but she was determined and didn’t have even a grain of sugar for the entire week,” says an insider, who notes that Kim also cut the amount of food she was eating, reducing her intake to 1,000 calories per day.