The guide I use (the Henry guide to portion sizes) says 2 servings of protein per day.
A serving for age 9 months to 2yrs is roughly:
1 egg
0.5 - 1 tbsp meat/fish/poultry/beans
So it's quite a small amount, but tbh so long as he is getting a balance diet across a week I personally wouldn't see the harm in having a larger amount of meat on the days you offer something he particularly likes and he'll likely choose to eat less on the days you offer something he isn't that keen on (like fish or beans). My LO is 15 months and will eat a full sausage or 1.5 fish fingers or several small bean burgers because he likes them, on another day he will have very little or no protein if he doesn't fancy what's on his plate.
For interest the serving sizes don't increase dramatically...
for 2-3 yrs:
1.5 tbsp meat/fish
1 fish finger
1 egg
1-2 tbsp beans
for 3-5yrs
1 slice meat (they fail to say what size the slice is
)
1 piece fish (ditto)
1 egg
1-2 fish fingers
2 tbsp beans
