At 13 months my daughter ate what we ate, with the exception of anything spicy and salad. And I don't think she was eatting beef yet, but she started not too long after. Now is the BEST time to get him used to big person food, because if you are making him seperate meals during his toddler years he will expect you to continue, and when do you stop? I started by kind of adapting our meals so she could eat them, but not much. If something had a spicy sauce or something I would take some out before putting the sauce on. Then I started giving her a little of the sauce. Kids need a variety of foods and flavors at this age- at between 18 and 20 months they will all of a sudden refuse to eat anything new, so take this opportunity to introduce new flavors while you can. And don't give up on foods- kids need to try things up to 7 times before they can develop a taste for them. If you do this now you will set yourself up for success during the more difficult preschool years! And you should also be encouraging him to feed himself as much as possible- I focused on turning anything into a finger food (spaghetti, anyone?) and gave her a toddler fork or spoon to practice with as well. Now she's an expert with a fork and spoon (I think the take and toss toddler utensils are best, and they're cheap). Slow down on the fruit and give him more vegetables, cooked well and cut small. Fruit is great, but avoid canned (they add a lot of sugar), and if you're feeding all fruit and no veggies your child will become used to the sweet and reject the relatively bitter taste of vegetables.
Good toddler foods:
Soft cooked pasta
whole wheat waffles
cereal (please not the sugary stuff!)
any vegetable, fresh or frozen and well cooked
chicken (make sure it's cut small until he gets used to it)
Crackers- yea goldfishies!
FRESH fruit (see below)
hot dogs- cut in half the long way (I know, not the healthiest choice, but there are nitrate free options, and we only do it occasionally!)
String cheese, or any cheese cut up
Applesauce (no sugar added)
Here are some meal examples that I fed to Izzy around that age:
Breakfast- frozen whole wheat waffle, cut up or cereal with milk (she started eatting cereal with milk right around this age- the milk makes it stick to the spoon, which makes it easier for them), or oatmeal cooked with fruit and milk
Lunch- we're a lot less formal for lunch than dinner, so I usually do whatever's quickest and easiest. We would always have a veggie- steamed or sauted peas, broccoli, or green beans usually, some rice (I usually have some pre-cooked in the fridge) or pasta, and a protein, either cheese, some diced ham, veggie or chicken nuggets, baked chicken, or something leftover from the night before.
Dinner- what I made for my husband or I! Izzy's favs: spaghetti (cut the noodles up well and prepare for a BIG mess) with either black beans or gr. turkey, tuna casserole (I know, weird), or anything with pasta, rice, or chicken (the girl LOVES chicken).
PS The canned/jarred "toddler" foods are a ripoff and not very nutritious. More toddler friendly- fresh orange sections, bananas, mangos, grapes (cut in half). And juice is bad! It's much better for toddlers to get accustomed to drinking water and milk. It sounds preachy, but I think juice is a "gateway drug" to soda, because it accustoms kids to drinking sweets.