Daily Protein Requirement
Your daily protein requirement is effected by several factors:
Recent studies have indicated that dietary protein has important roles in cell signaling, hunger and satiety, metabolic temperature regulation and blood sugar regulation, and that each of these roles is dependent upon optimal amounts of protein intake and the resulting amino acid availability in the body.
But there are differing opinions on the subject of a daily protein requirement from several highly respected authorities. I've summarized their positions, as I interpret them, below:
Dr. Ron Rosedale
Dr. Ron Rosedale , a pioneer in Leptin research, talks about protein requirements being lower than recommended by some. He discusses his reasoning here, and associates higher protein intakes with higher blood sugar.
Dr. Rosedale recommends 1 gram of protein per kilogram of ideal body weight, minus 10%. So for instance, if your ideal body weight is 150 pounds:
Dr. Donald Layman
Dr. Donald Layman, a nutrition professor and research scientist from the University of Illinois at Urbana-Champaign has been researching the effects of dietary protein for 3 decades.
He recently did a podcast with Jimmy Moore, and had some interesting things to say about protein consumption.
Dr. Layman's research on the effects of a daily protein requirement shows that:
Lyle McDonaldLyle McDonald, in his book The Ketogenic Diet explains that because of the metabolic adaptations which happen as the time spent on a ketogenic diet increases, the daily protein requirement is higher during the first three weeks on the diet than it is once the body has adapted through ketosis.
His calculations are based on what studies have shown about brain glucose requirements when carbohydrate or food intake is restricted.
At the beginning of a ketogenic diet, the brain requires a larger amount of glucose. To spare muscles from being converted to glucose to supply the brain, a dietary protein intake of 150 grams per day is suggested to minimize the loss of muscle mass to glucose production.
However, after 3 weeks on a ketogenic diet, the body has adapted to ketosis and the brain is using ketone bodies for fuel for the most part. This adaptation means a much smaller amount of glucose is needed for brain function. At this point, the daily protein requirement drops significantly, and only about 50 grams of dietary protein are needed per day to spare muscle mass. (He notes that intense exercise or a higher carb intake would alter these recommendations to some extent).
In the real world, I've found a good indicator which alerts me that I'm not eating enough protein - my eyes get very dry, especially at night. Eating more protein resolves the issue for me. I believe this has to do with the body reducing mucus production when protein intake is too low. (Lucas Tafur talks about this here).
Dr. Jeff Volek, Dr. Eric Westman, and Dr. Steve Phinney
In contrast, Dr. Westman, Dr. Phinney, and Dr. Volek recommend a higher protein intake. Their book "New Atkins for a New You: The Ultimate Diet for Shedding Weight and Feeling Great" recommends a daily protein requirement as follows:
These are daily totals. Remember to divide the total ounces by the number of meals you are eating. For instance, if your total daily protein requirement is 18 ounces of protein, and you eat three meals a day, you would divide 18 by 3, and eat 6 ounces of protein at each meal.
Here's a quick reference to help you figure out how to follow a daily protein requirement on a visual basis. An ounce of protein looks like:
Other Sources of Information on Protein RequirementsThere's an excellent blog post on the Ketotic.org website about protein requirements.
And here's a great interview with Dr. Jeff Volek on the individual variations in low carb diet implementation.
For those who want to dig deeper: