Income: money in (gross). Profit: money after expenses (net).

While humans have to pay income tax (because the government is afraid we'd have no money left to tax because we'd spend it all), business pays tax on profit. This means that they can totally "expense" more in a year and pay less tax. The only thing preventing that are stockholders, who often like profit as it gives them dividends and makes the stock more desirable and drives the price of the stock up. This assumes that there is a large number of stockholders and not a filthy rich Food Barron holding all the stock (a la Weston).