Every country that has a problem with starvation has huge population growth. They have at least 2.5% population growth yearly which translates to doubling popu

Every country that has a problem with starvation has huge population growth. They have at least 2.5% population growth yearly which translates to doubling population in 28 years, while some have as high as 4.5% which means they double every 15-16 years. If a population has a food problem, why does it double every 15 years?