Using IF statements to reduce no of Loop iterations

variable 'size' is the size of the larger list.

for(int x = 0; x < size; x++){

if(employees!= null && employees.size() > x){
//do something
}

if(consultants!= null && consultants.size() > x){ 
// do something
}

Then i have another way of doing it

for(Object obj : employees){
//do something
}

for(Object obj : consultants){
//do something
}

The second approach seems simpler to me, but the first approach would result in lower loop iterations. anyways, i would like to know which would be better in a general situation.