Caloric content of common fruits: a. The fruit with the most calories, over 700 calories per pound, is the oily fruit of trees found in South America. Which one is it? b. The fruit with the least calories, around 70 calories per pound, is a fleshy, wate

The caloric density of most fruits comes from their sugar content, but the champion of high-calorie fruits breaks this rule. The avocado, a native of South and Central America, derives its impressive calorie count from its high concentration of healthy monounsaturated fats. Fat is more than twice as calorie-dense as carbohydrates or protein, which explains why this oily, creamy fruit packs over 700 calories per pound. Botanically, the avocado is a large berry with a single seed. Despite its high calorie count, its abundance of healthy fats, fiber, and vitamins makes it a remarkably nutrient-dense food.

On the opposite end of the spectrum lies the cucumber, a fruit we commonly treat as a vegetable. Its incredibly low calorie count, around 70 calories per pound, is due to its composition: it is over 95% water. This high water content leaves very little room for calorie-containing sugars, fats, or proteins. As a member of the gourd family, along with melons and squash, the cucumber's primary nutritional contribution is hydration. This stark contrast demonstrates how a fruit's caloric value is determined by its unique balance of water, sugar, and fat.