Some opponents to meat eating diets say that eating too much protein creates an ammonia overload. As your liver can handle levels of 600g a day or more without problem (assuming it is healthy), you would have to eat over 20 quarter pounders a day to hit this level!
First, what is the recommended level. The last stat from the government is that 10-35% of your energy should come from protein. For women, this starts with a base level of about 2400 calories. There are 4 calories per 1 gram of protein. So if you say 35% of your calories come from protein, that is 840 calories total - meaning 210g of protein a day. Let's look at some typical things you are likely to eat:
quarter pounder burger: 30g
t-bone 10oz steak: 70g
chicken breast: 42g
1/2 salmon fillet: 39g
1 cup tunafish: 43g
As you can see, it would be hard to even achieve your proper calories per day from protein without some work. The chance of reaching too-high levels, if your liver is healthy, is pretty slim. Of course, if you have a liver disease, be sure to talk with your doctor about your nutritional needs.
Myths about Protein Consumption