True but I would be more specific than that. Basically we have two major trends going on:
1. Calories in per capita are falling slower than calories out per capita. For traditional, hand-tool-based farming, it required a lot of calories. Even animal-powered farming required a lot more than is required today. It's a bloody lot of hard manual work as my British friends would say. When one talks about net calories, one has to recognize that a hundred years ago people had to eat a lot more than today.
2. More reliance on high tech foods (HCFS, hydrogenated oils, etc, but also see frozen dinners, often which are loaded by excess corn sugar and oil). These are far from ideal dietary-wise.
These combine to mean fewer micronutrients, and an excess of macronutrients. But the lack of hard physical labor as the normal way of life is a major part of things.