Latest findings advise caffeine intake to be 400 mg a day for adults (200mg for pregnant ladies) and 100mg for teenagers. If you find yourself flagging, often all you need is hydration or a snack…some fresh fruit or wholegrain toast. A snack such as dried fruit or fruit juice will give you the quicker lift but will be higher in calories.
But coffee is a wonderful thing so don’t deprive yourself of it, just keep it in check or go for decaf.
Having tried so many over the years I can definitely recommend
Asda’s Anytime Decaffeinated Ground Coffee.