I'm not going to try doing this, as I eat 6 meals a day, about 4000 Kcal in total. But since dinner for me is about 2000 Kcal and that's about what normal people eat during the whole day, it should be possible for most. Not only that, it used to be normal eating habits for many millenia:
Breakfast as we know it didn't exist for large parts of history. The Romans didn't really eat it, usually consuming only one meal a day around noon, says food historian Caroline Yeldham. In fact, breakfast was actively frowned upon. "The Romans believed it was healthier to eat only one meal a day," she says. "They were obsessed with digestion and eating more than one meal was considered a form of gluttony. This thinking impacted on the way people ate for a very long time."
From the Roman times to the Middle Ages everyone ate in the middle of the day, but it was called dinner and was the main meal of the day. Lunch as we know it didn't exist - not even the word.
So, is it then healthier to eat one meal a day or are modern eating habits healthier?