Not sure which Beneful you have . I would advise you to feed a kibble with a named meat source as first ingredient. You will prolly be able to find a better quality kibble with no corn , wheat or soy for no more than you are paying for the Beneful if you have a farm/feed store in your area.
Helpful note: I try to alway make sure that the kibble I am buying has a fat content of 12% to 15% . Food containing 10% or less fat may cause a problem with not enough fat to digest fat-soluble vitamins.
I have 2 dogs....one about 3yrs old (guard dog-heinz57) and a beagle pup about 9 mo old. I feed them the best commercial dry food I can find, and fortify it with pork, chicken, and fish bones about 3 times a week.....they are both in beautiful shape, but I must be careful to not overfeed the beagle.
You know them....they don't know when to stop.