Iron deficiency affects more than 1 in 5 women in the US. Being deficient in essential minerals can show up in all kinds of ways but an iron deficiency can also be a blow for getting into your skinny jeans with relative ease. See, your body can't work as efficiently to burn calories when it doesn’t have what it needs to work properly. A cup of lentils, it turns out, provides over a third of your daily iron needs. Legumes like lentils also have been shown to drive down bad cholesterol and blood pressure.