Protein and vegetarianism

Shovelita

I'm making this tonight with lots of extra beans, I had beet burgers (which are mostly lentils) off this same site for lunch. I been trying to make at least 2 of my meals a day be bean-based. The trackers on this site say I need like, 70 grams, which i just havn't been able to do. I been aiming to just get to 40-50.

http://www.theppk.com/2011/09/okra-gumbo-with-chickpeas-kidney-beans/

VeganCappy

This article explains the process of how the numbers were achieved.

"Human nitrogen requirements are usually determined from the nitrogen balance. The usual procedure is to regress nitrogen balance on intake and to define the requirement as the intake level that would produce a zero balance, i.e., equality of dietary N intake and N losses (Fig. 1). Nitrogen losses occur in different ways. They mainly arise from urinary losses in the form of urea, ammonia and creatinine but also in the form of fecal and miscellaneous losses (Calloway and Margen 1971) (Table 1). Minimum nitrogen losses [“obligatory nitrogen losses” (ONL)] were measured in subjects fed a protein-free diet for 1 week. Under these conditions, nitrogen losses were estimated at 36 mg/kg/d in urine, 12 mg/kg/d in feces and 8 mg/kg/d in miscellaneous nitrogen losses (sweat, sebum, desquamations, nails, hairs and saliva) (Manatt and Garcia 1992). Obligatory oxidative losses and indispensable ileal amino acid losses have been reported to reach 162 and 18 mg/kg/d, respectively (Fuller et al. 1994, Young et al. 1989) (Table 2). We determined total ileal nitrogen losses as reaching 9 mg/kg/d, i.e., 16% of ONL. Indispensable ileal amino acid losses represent ∼10% of obligatory oxidative losses. From these estimations, ONL represent 54 mg/kg/d and correspond to a protein requirement level of 0.34 g/kg/d (FAO/WHO, 1985). Because dietary protein utilization does not achieve 100% efficiency, it has been suggested that an intake of 0.6 g/kg/d of well-balanced protein will achieve a zero nitrogen balance. The adequacy of this diet has been reported in studies conducted over 2- or 3-mo periods (FAO/WHO 1985). A safety coefficient is added to this figure so that the final recommendation for dietary protein is 0.75 g/kg/d. In children, the requirements for growth must be integrated in addition to maintenance requirements."

http://ajcn.nutrition.org/content/77/1/109.full

They base it on moderate activity. So, a 70 kg individual would have a daily energy requirement of 2,700 calories. So these roughly come out to 3.5% protein by calories needed, 6.2% to compensate for utilization efficiency, and 7.7% for the safety coefficient.

"There is a trend toward an increase in the nitrogen balance when nitrogen intakes are increased"

This observations are particularly telling when combined with these ones:

"In studies of the obligatory nitrogen loss, subjects fed a protein- free diet took between 10 and 17 days to achieve a constant low level of urea nitrogen excretion (28). In studies involving diets in which protein intakes were reduced from adequate to 0.35 g/kg per day, adult men took from 7 to 28 days to achieve nitrogen equilibrium (29). The subjects studied by Oddoye & Margen (27) took from 16 to >40 days to achieve balance after the reduction in intake from 3 to 1 g protein/kg per day."

This suggests the body maintains a limited range of amino acids as a ratio of protein intake. If there is less protein intake, the body might believe there to be less total energy intake leading to less activity and doesn't maintain the store of amino acids. If there is more protein, the body sees it as a likely increase in total energy consumption and increase the store of amino acids for repairing and rebuilding. Of course this is a limited range as 1.8g/km is the highest protein consumption shown to effect nitrogen balance. This was for body builders, and if we assume an extra 1,000 calories a day consumed (The subjects were working out for 1.5 hours, 6 days a week), then that comes out to around 13.6% protein by calories. Anything more showed no benefit.

*Going over my notes, I see that 1.6g/km was the highest protein consumption to show an effect of nitrogen balance in bodybuilders. Comes out to around 12% protein by calories. 1.8g/km was used during caloric deficient training and shown to be protective against muscle loss when compared to .9g/km.