Black coffee, which is basically zero calories – can be a substitute for other high calorie drinks.
But few people drink black coffee today – just watch the order line at Starbucks – customers order high calorie drinks, often many hundreds of calories, including dairy and sugar. And not in 6-8 oz cups but 12-21 oz typical.
Further, you need a LOT of caffeine to change metabolism by a little bit:
However, large doses of caffeine may be required to significantly influence metabolism.
For example, one study found that a caffeine dose of 4.5 mg per pound of body weight (10 mg per kg) increased metabolism by up to 13%. This would equal 680 mg of caffeine — a whopping 7 cups (1,660 ml) of coffee for someone who weighs 150 pounds (68 kg)
Source: How Does Coffee Affect Weight?
On the flip side, coffee may disrupt sleep, making physical activity more difficult.
Coffee may affect cortisol levels, leading to weight gain.
Coffee – as it is normally consumed with dairy and sugar – may lead to weight gain, disruption of blood sugar and insulin levels and more.
