Give you a lift

Hit a slump? The caffeine in coffee can give you a quick boost. Caffeine has been shown to increase alertness, improve mood, enhance cognitive function, and make you feel less tired. Studies suggest that a low to moderate intake of coffee—anywhere from about 38 mg caffeine per day (roughly 1/3 of a cup) up to 400 mg per day (equivalent to roughly 4 cups)—appears to be safe for most healthy adults, according to the FDA. And a meta-analysis (a thoughtful review of several studies) suggests habitual drinkers saw greater cognitive and mood benefits than non-drinkers.