How much am I undercutting gains if I slack on protein?

Question

In this question, the accepted answer for daily protein needs cites, "0.8g/lb ... (body-building)", meaning that if one is body building, one needs 0.8 g of protein per day per lb of body weight. I'm not trying to be a "body builder" in the sense of competitions, but I am trying to build my muscles, strength, and endurance, and so I used this figure. (Perhaps that is inappropriate?).

The problem: I am largely vegetarian (much of which is vegan), 170 lbs, and find that getting 0.8 * 170 = 136 grams of protein, each day, into my diet seems very tough--particularly since I am trying to lose fat while gaining muscle, and so am trying to keep calories low enough to lose fat. I generally don't eat breakfast and my lunch is about 20 g of protein, so this leaves a 116 g at dinner....nearly impossible for me based on my typical diet.

Although I've been lifting weights on and off for about a year and a half, I'm sure I've rarely if ever hit that 136 gram amount. I have clearly made some gains over that time (going from 0 pull-ups to 11), but generally am dissatisfied with my strength and endurance progress. Part of that is clearly an insufficient training regimen, which I can work on, but I've wondered if I am working at a sizable disadvantage by not consistently hitting this 136 grams.

RELATED QUESTIONS:

1. So, first, to be clear: is that full body weight or only lean body mass?
2. As someone who wants to do a modest-medium transformation (lose 20 lbs of fat, gain maybe 10 lbs of muscle?...within 6-10 mos?), is the 0.8 g/lb of body weight the right value?
3. To what degree could "under-proteinizing" my diet be holding back progress?

Answer 1

Let's start from the bare minimum requirements, which based on different places I've seen is around 1g per kg lean body weight. That's roughly 0.5g per pound lean body weight. This number is the amount of protein required to maintain muscle mass in sedentary people.

When you lift weights, your body has an increased demand for protein. Whether you are increasing your sarcoplasmic hypertrophy (support systems and fluid in the muscle cells), or you are aiming to increase your myophibrillar hypertrophy (protein pairs to build strength in the muscle cells), your body needs more protein than a sedentary person. The worn out bits of your muscles get replaced with new bits, and your body has to have more to supercompensate (handle more weight than before).

To tell the truth, .8g per pound of body weight is the lowest number I've seen for weightlifters anywhere. Normally it's about 1g or 1.5g protein per pound body weight. Note, protein content this high in your diet will also help you stay satiated longer, and be a bit more thermogenic (i.e. burn more Calories just processing it). While this may be a little more than your body can use, most proteins don't have a 100% metabolism efficiency. What that means is that you don't get all the protein you eat, even when you don't eat enough. Weightlifters have to consume more protein to get the maximum amount the body can use.

It's true that vegetarians are at a disadvantage here. Depending on "how vegetarian" you are, there are things you can do to help yourself out. For example, if you don't have any issues with dairy protein (a cow does not have to die to give that to you), you may consider supplementing with whey protein. Soy protein also has a fairly complete amino profile, but has the disadvantage of being a phyto-estrogen component in your body (acts like the estrogen hormone).

Bottom line: weightlifting, whether for aesthetics or strength (or both), demands more protein to continue building muscle than the average sedentary person. You will likely have to turn to supplementation to get the extra protein you need. If you have a higher proportion of protein in your diet (amongst all the Calories you eat), it will help you burn more fat.

Side comment: The industry that pushes the need for breakfast is the cereal industry. Studies advocating intermittent fasting put less emphasis on what time of day you eat, and more on getting the right nutrient profile when you eat. Whether you have breakfast or not isn't going to affect your gains, as long as you get the Calories your body needs, and the proper macronutrient proportions to support muscle growth and recovery (carbs are useful for recovery, but not too many).

Answer 2

Protein intake is the most important factor in muscle recovery and building, if you skimp on protein intake, and cut calories, your body will start breaking down muscle to get the needed protein.

You can cut down on starchy carbs all you want, but try to make up the daily protein as far as possible, I don't think you need the body building level, but I would go with about half a gram per lb of total body weight.

Another thing I noticed in your question is that you generally don't eat breakfast, and that your main aim is to lose weight. You will need to make breakfast a daily habit for optimal weight loss, if you really want to skip a meal, or cut down, rather skip dinner then.