The One MAJOR Scientific Disadvantage To Being The First-Born Sister

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Who knew!?

Your parents, grandma, or favorite over-opinionated aunt may have compared you to your sister at every family gathering. Your body is constantly picked apart because it's so unlike your little sister, who's shaped like Kendall Jenner, while you're of a more Kim Kardashian design.

Luckily, there's a new study that might explain why your younger sister weighs less than you, and the findings may surprise you.

An article in Today discussed a Swedish study where "more than 26,000 Swedish women found that firstborns were nearly 30 percent more likely to be overweight and 40 percent more likely to be obese than their younger siblings were."

The study also found that firstborn men are not only prone to be heavier than their younger brother, but are unfortunately "more likely to develop high blood pressure and insulin resistance."

Today's piece poses the idea that this may be an explanation for the rise in obesity. Since less people are having more than one child, there are more kids with this 30 and 40 percent "overweight likeliness" populating the planet. But there are positives to this study.

This may sound like firstborns are fated to be fat, but the new research isn't so pessimistic. Instead, it provides a possible answer as to why you and your sister have different body types, and why it seems impossible for either of you to achieve your desired body.

The positive point is: your shift in weight is neither sibling's fault. Interestingly enough, this study doesn't blame genetics for the difference in sizes either; instead, it’s all about the mother's uterus.

Because the uterus is much more constricted during the first pregnancy, scientists believe that "firstborns were exposed to in utero compromise, which reprograms metabolism and the regulation of fat," thus causing firstborns to have a slower metabolism than their younger siblings who were housed in expanded utero conditions.

This research suggests that even from the womb, environment plays a key role in being overweight.

But there are a few pros we can take away: the possible explanation as to why siblings are shaped drastically differently, the motivation to find the right diet or exercise program that targets specific metabolic needs. Plus, the next time someone says, "Why aren't you skinny like your little sister?" you can make them feel awkward by responding, "Because my mother was too tight."



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