So what happens if you don't get enough protein?

I'm not sure how you arrived at 128g of protein but an adult male endurance athlete only needs about 84-118g per day. 128g seems very high and unattainable really unless you take in a lot of protein in the form of shakes and bars (which are generally disgusting and full of sugar).

I'm not sure how you arrived at 128g of protein but an adult male endurance athlete only needs about 84-118g per day. 128g seems very high and unattainable really unless you take in a lot of protein in the form of shakes and bars (which are generally disgusting and full of sugar).

I get about 140 grams per day mainly from chicken and low calorie/ high protein seafood. I only have a shake or a bar every other day or so and sometimes less often than that. When I do ear bars or homemade protein shakes, they contain very little sugar.

I borrowed this from the Eat, Train, Progress group; originally posted by Chief_Rocka

The purpose of this is not to try to pinpoint what an "optimal" protein intake is, I'm not sure we'll ever have a concrete answer to that question anyway. Absent any evidence that high protein intake is harmful, there's really no good reason to take a mimilist approach to protein intake.

The current RDA for protein intake is .8g/kg of bodyweight. The real kicker here is that they claim that there is no benefit to eating more than that. I simply want to arm people with research that disputes this.

So, here we go:

1.4-2g of protein per kg of bodyweight is beneficial for individuals engaged in intense exercise:
http://www.ncbi.nlm.nih.gov/pubmed/20048505
http://www.ncbi.nlm.nih.gov/pubmed/19278045
http://www.ncbi.nlm.nih.gov/pubmed/17908291
http://www.ncbi.nlm.nih.gov/pubmed/18500966

2-3g/kg is beneficial for athletes:
http://www.ncbi.nlm.nih.gov/pubmed/14971434

Older subjects lost lean mass getting the RDA protein recommendations (.8g/kg):
http://www.ncbi.nlm.nih.gov/pubmed/11382798

Double the RDA outperformed the RDA for individuals in a calorie deficit:
http://www.ncbi.nlm.nih.gov/pubmed/495538
http://www.ncbi.nlm.nih.gov/pubmed/16046715

Triple the RDA outperformed the RDA for individuals in a calorie deficit: http://www.ncbi.nlm.nih.gov/pubmed/19927027

Subjects with a 1.5g/kg protein intake lost fat and gained lean mass:
http://www.ncbi.nlm.nih.gov/pubmed/10838463

Of people that don't exercise, high protien intake causes less lean-mass loss:
http://www.ncbi.nlm.nih.gov/pubmed/17299116

All the links are peer reviewed studies that prove the importance of high protein intake for athletes and dieters.

People like to throw out the idea that you only need a very low amount of protein. The problem with that is that need and optimal are not synonyms.

[Edited] According to US Centers for Disease Control and Prevention (CDC; http://www.cdc.gov/nutrition/everyone/basics/protein.html#How much protein):
"In general, it's recommended that 10-35% of your daily calories come from protein. Below are the Recommended Dietary Allowances (RDA) for different age groups"...
- Girls/Women ages 14-70+: 46g
- Men ages 19-70+: 56g

This may provide context for above literature citations referring to RDA. Defer to literature regarding impact of varying protein levels.

So if I don't hit the recommended gram/LBM, I won't maintain muscle?

I had eggs for breakfast, fish for lunch and dinner (2 different kinds - just happened that way) and almonds for a snack, and I'm at like 78 g of protein. I'm supposed to be aiming for 128g, but I only have about 283 calories left for the day. This is a LOT harder than I thought it would be.

I wish I could stomach yogurt.

It's not quite that cut-and-dried, but you have the basic concept. If you don't take in adequate protein, over time, you're in danger of losing more muscle. Any time you lose weight, you lose some muscle (as well as fat, water, etc.), but the goal is to keep as much of your muscle as possible.

Your protein goal seems super high, though. What is your daily calorie goal, and your target macros?

The general recommendation is 0.8g-1g per pound of lean body mass, so just making up numbers, here is how you'd find your target:

If you weigh 150 pounds and have 25% body fat, you have 75% lean body mass. 150 x .75 = 112.5 pounds of lean body mass, so you'd want 90-112g of protein.

1. Eating at a caloric deficit (i.e. dieting) causes your body to metabolize NOT ONLY your fat mass, but also your lean mass (muscles and organs). Eating more protein can really help discourage your body from doing too much of that. It will minimize lean mass loss while you're dieting. Plus it can help make sure your muscles are getting the best results they can (given your caloric deficit) from resistance-based exercise.

2. Protein makes you feel more satisfied, for a longer time, after eating. You can eat smaller meals and feel better about it. Protein is satiating.

3. Protein is a bit more difficult for your body to metabolize than carbs or fat. There is a "metabolic cost" to eating protein -- basically it takes more calories to actually burn it, so the "net calories" from protein are 5%-15% lower than the actual calories in the food. (This is probably the least important consideration, because measuring that metabolic cost is kind of silly! Dietary fat also has a higher metabolic cost per gram than carbohydrate, though not as great.)

What will happen if you don't get enough? Well, given that "enough" is a matter of quite some debate, it depends on how low "not enough" means to you! But generally, you could be hungrier, and as you lose weight a greater proportion of your weightloss would be from lean mass, which is a bit self-defeating. You'd have to lose more weight overall to achieve the size you want, and even then you'd have less muscle definition and less strength. You'd potentially get a "wasted" look rather than a healthy slim look.

Not meeting the super-high protein goals many dieters (and bodybuilders) set is not the end of the world. You will still lose weight (and fat) at a caloric deficit if you feel good (satiated and strong) based on the dietary goals you are following. But getting more protein can help many people feel better, perform better athletically, and marginally improve overall results.