He ate 2 * 1 = <<2*1=2>>2 pounds of broccoli
There are 51 / 3 = <<51/3=17>>17 calories in each pound of broccoli
So he ate 2 * 17 = <<2*17=34>>34 calories of broccoli
He ate 1 * 51 = <<1*51=51>>51 calories of carrots
So in total he ate 51 + 34 = <<51+34=85>>85 calories
#### 85