No 1600 is not enough. Health organizations such as WHO (World Health Organization) have studied groups of people from all over the world, different races, sizes, religions, and dietary habits. They have discovered that eating 2000 calories a day only wards of starvation and a slow death by malnutrition. Most health organizations would advocate 2400-3000 calories a day.
We recommend 2500 minimum a day for couch potato females. More if you are active.
Eat more to live more and live more to eat more.
Reasons include adequate protein, lipid, energy and nutrient intake such as vitamins, minerals, phytochemicals, chlorophyll, building healthy cells, tissues, bones and warding off osteoporosis, and dental health etc.
Think of your stomach as a muscle. You dont use it, it will atrophy and then when food consumption increases, it will hurt. You have to exercise this muscle.
Instead of eating 3 big meals, try 4-5 smaller meals throughout day.
Also, get at least 10% of calories from fats for regulation of fat soluble nutrients. If you are active and eating enough calories, that is almost one avocado, or 1-3 oz of nuts and seeds.
Higher fat foods also tend to be high calorie, and raw vegan, nutrient dense. A handful of nuts or seeds is a quick n easy way to get the calories and nutrients in.
I concur with Shells blog recommendation.
I would also like to add that being properly hydrated helps. Many people here drink 2-4 cups of water in the morning, then wait about 20 minutes, and then eat. Eating on a hydrated digestive system is much easier than dehydrated.
Also, taking fluids outside of meals leaves room for more calories and dietary intake.