I collected few important reasons from various articles and I hope you would find them helpful :)

In a study published in the American Journal of Epidemiology, researchers found that those who skipped breakfast were more likely to be not just overweight, but obese!
SOURCE : (www.care2.com)

Studies have shown that eating breakfast actually makes your blood sugar and insulin levels rise more slowly throughout the day, and can thus make you less likely to “crash” from all the ups and downs your blood sugar and insulin takes.
SOURCE : (www.care2.com)

Studies have shown that people who eat breakfast have lower cholesterol levels, smaller waist lines, and less insulin in their blood.
SOURCE : (www.care2.com)

studies have shown the positive impact that eating a healthy and balanced breakfast has on our brain’s ability to function — boosting your concentration and short-term memory.
SOURCE : (www.care2.com)

Whether you're dieting or not, breakfast is a great way to help burn those unwanted calories. By eating smaller meals throughout the day, you're increasing your body's metabolism. In fact, research conducted by Harvard of 17,000 men discovered "that those who frequently ate breakfast cereal--both refined grain or the whole-grain types--consistently weighed less than those who rarely or never ate breakfast cereal."
SOURCE : (www.inc.com)

Food is fuel for the body, so eating a nutritious breakfast means you’ll have enough energy to burn, keeping you active and productive until lunch rolls around.
SOURCE : (www.naturallivingideas.com)

Didn’t have time for breakfast and by mid-morning all you can think of is a delicious sugary pastry?
That’s because skipping breakfast makes high calorie food seem more appealing later in the day, according to a study. Our brains crave these calorie laden snacks to make up for what we missed out on when ‘fasting’.
SOURCE : (www.naturallivingideas.com)

A Dutch study has shown that a substantial breakfast boosts the body’s gamma-interferon, a natural antiviral that boosts immune function.
Cardiff University researchers also claim that people who skip breakfast are more prone to infections – perhaps because white blood cells, which fight infection, need a morning boost.
SOURCE : (www.naturallivingideas.com)