While raisins are often suggested as a snack for weight gain, they are very dense in sugar and can curb a toddler's appetite for more nutrient-dense meals. Pediatricians and nutritionists generally recommend avoiding them as a regular snack. Instead, focus on a balanced variety of whole foods to support healthy growth. If your child is on the lower end of the weight spectrum but is active and meeting milestones, prioritize protein and healthy fats rather than concentrated sugar sources.