Having A Younger Sister Makes You More Likely To Get Fat

Having a sister is the best. Sisters are there to give you advice (or seek yours), support you 100%, and basically be your partner in crime. Unfortunately, there are also some downsides to having a little sibling. If your sister is younger than you, new research suggests that you’re more likely to be overweight.

  1. It sucks but it’s true. According to a study of 13,406 pairs of Swedish sisters born between 1991 and 2009, the first-born sisters are way more likely to be overweight or obese than the younger ones. Uh oh.
  2. It wasn’t always this way. The older sisters tended to be lighter than the younger ones at birth, but when they grew up and became adults, the older sisters had a 2.4% higher BMI than their baby sisters. That may not seem like a big amount, but it is a noticeable difference.
  3. This is a big problem, no pun intended. The research further proved that older sisters were 29% more likely to be overweight than their younger sisters and 40% more likely to be obese. What’s up with that?
  4. There’s a possible explanation for why it happens. According to Professor Wayne Cutfield from the Liggins Institute at the University of Auckland, the blood vessels which send nutrients to fetuses are smaller during first pregnancies. Because of this, the fetus is more likely to store fat and have greater insulin resistance.
  5. Moms could be to blame too. There’s also the possibility that mothers will overfeed their first babies, leading to the child developing poor dietary habits that stay with them throughout life. There are other possible psychological reasons, but more research needs to be done before the real reasons can be isolated. However, this is an interesting trend to note and it’s worth thinking about why this might be the case. At least the older sisters among us can start watching the scales a bit more (if that’s something you care about, of course – there are worse things in life than being a little heavier).
Piper Ryan is a NYC-based writer and matchmaker who works to bring millennials who are sick of dating apps and the bar scene together in an organic and efficient way. To date, she's paired up more than 120 couples, many of whom have gone on to get married. Her work has been highlighted in The New York Times, Time Out New York, The Cut, and many more.

In addition to runnnig her own business, Piper is passionate about charity work, advocating for vulnerable women and children in her local area and across the country. She is currently working on her first book, a non-fiction collection of stories focusing on female empowerment.
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