I always feel out of energy for about three hours after i eat lunch. why is this happening?

What are U eating: Meals heavily weighted in carbohydrates are more likely to lead to a quicker let down and this could be both your lunch and your earlier breakfast.Midday activities are often sustained more by your breakfast than your lunch, which is still being processed in your gut. A balanced breakfast with protein, fat and some carbs is more likely to sustain you midday than a quick bagel/etc.