Hi. I think your question is a good one, because it motivated me to look back thru my files. It's not as straightforward as "eat a boca or two" for dinner. You have to do a tiny bit of label reading.
For the meal (I preferred lunch) that you want to substitute vegetarian choices for "8 oz raw meat", use the following "rules":
1. Aim for 30g to 40g of protein.
2. The carbs need to stay below 8g net (total g minus fiber g); if they exceed 8g, then no restricted IP that day.
3. The fat is kind of a guess, target around 5g but occasionally up to 10g is OK.
I also have a note that says 1/2 cup of strained lowfat cottage cheese is one serving, but I never did that on Phase 1. (I'm assuming you are not vegan. If you search the old threads you will find at least one poster who is.)
I used Gardein products during 2011 and 2012, but these products have been reformulated and nearly all of them are too low in protein, too high in carbs and too high in fat, especially for Phase 1.
If you check out the "chicken strips" of the Beyond Meat brand, I think those will be a good choice for you. Sometimes you need to eat more than 1 serving of a product but less than two. You can also combine products to meet your macro (protein/carb/fat/calorie) goal.
You can use Boca burgers IF you have selected the ones that are higher in protein and lower in carbs. Some of the varieties are OK and some will not really work.
Unless you are vegan or just don't like them, I suggest eating eggs (is it now 2 whole eggs and 4 egg whites?) at least once a week. Also, tofu is on the list. There are some higher protein tofu products; you can have 8 oz or you can adjust it to fit the macros. There are also some of the tempeh products that work, and even some of the seitans. Some of the Quorn products and the Tofurkey luncheon meats might also be used.
Your goal should be to find a variety of products as you are going to continue to rely on protein as a mainstay when you get to maintenance. You don't have to find them all the first week! ; )
Another suggestion is to find and use the less processed items, like eggs and tofu, and be sure to rotate thru the other ones. There are also Black Soy Beans which are canned (one brand is Eden), which are very low in carbs. Those used to be the choices back in early 2011.
It's a lot of information to throw out there, so feel free to ask any questions you might have.
Related, I think part of being successful on IP is getting in that protein/vegetables is a meal mindset. Having some prepared vegetarian product that is already flavored up and ready to go (like a Boca) makes it easy but doesn't really teach us how to use herbs, spices or vegetable mixes to help food taste good and be less processed. Of course the flip side is, when you are having 3 packets a day what is one more processed product? It depends on how you want to use the IP journey -- to get to goal or to get to goal AND learn some tools you need in maintenance (even if that just means knowing what products to buy).
Hope that helps.
194.4/120 started IP 11.2.11, P4 117.3-120.3, officially from Aug 2012 to Jan 2013
2014 reset: Ja22 124.2 to Fe19 116.8
2015: struggling after shoulder injuries & can't lift weights like I used to, hanging in at 130 and trying to get back into the low 120s
2016: been back at the gym since Dec '15 and just really need to reset, stopping at a reasonable spot