A news report has said that researchers believe that the amount of weight that a mother gains during pregnancy can lead to her having an overweight toddler.
Women in the study who gained the recommended amount of weight ran four times the risk of having a child who was overweight at age 3, compared to women who gained less than the advised amount.
I had two large babies that both grew into chunky toddlers. However, as they got older they began to slim down. One thing this news story did not mention is the amount of activity the children had and the amount of calories the children actually took in during 
the day.
Dr. Phil had a follow-up show about a young boy that was extremely obese and had a mother that believed his obesity was due to some undiscovered medical condition. When the child went to live with his father and changed his eating habits, and amount of physical activity had then he lost tons of weight.
Having a chunky toddler does not mean that there is a life sentence to obesity. It just means that we, as parents, must work hard to teach our children good exercise and eating habits that they will take with them into adulthood.