If it takes too much effort just to get ready for the day, your diet is probably lacking in iron. One of iron's many duties is to help boost energy levels by transporting oxygen throughout the body. But when you're not ingesting enough iron, your body isn't making enough of those essential red blood cells that transport oxygen and keep you energized for the day. One of the biggest symptoms of anemia (when your blood is low in iron) is low energy levels and sluggishness, according to the Cleveland Clinic Center for Continuing Education. If you have anemia, take iron supplements and incorporate some of The Best Iron Rich Foods into your diet to pump up oxygen flow and energy into your body.
Source : http://uk.businessinsider.com/warning-signs-that-you-need-to-change-your-diet-2017-10