Researchers at the University of Nevada-Reno have found that used coffee grounds can be converted into biodiesel, potentially powering cars with fuel that smells like cappuccino. However, doctors caution that your first morning cup of coffee might not be the healthiest way to start your day.

Health experts recommend delaying coffee consumption until mid- to late-morning (between 9:30 a.m. and 11:30 a.m.) because drinking it on an empty stomach can spike stress hormones and, when combined with sugar, cause blood sugar crashes leading to fatigue.

Coffee also interferes with the absorption of essential minerals like iron, magnesium, calcium, and B vitamins, which support bone health, nerves, and energy. It can disrupt digestion, worsen symptoms for lactose-intolerant individuals, and amplify anxiety or jitteriness by increasing stress hormone levels.

Early coffee intake may disrupt sleep, cause dehydration, and increase cravings for sugary snacks, potentially leading to weight gain and skin issues. Experts suggest pairing coffee with a balanced breakfast or waiting until later in the morning for a healthier energy boost.