Hope's Edge_ The Next Diet for a Small Planet - Frances Moore Lappe [90]
Figure 16, “Summary of Complementary Protein Relationships,” illustrates the basic combinations of foods whose proteins complement each other. The dishes listed are meant to be suggestive of the almost endless possibilities using each combination. (Complete protein tables are in Appendix E.)
The Complementarity Debate
Since the first edition of Diet for a Small Planet, many have pointed out that it is not really necessary to eat complementary proteins in the same meal, as I implied. They are right, technically. But experimental evidence suggests that protein assembly will slow down after several hours if all of the amino acids are not present. “If a diet lacks only one essential amino acid, which is provided several hours later, efficient use of all amino acids falls,” says a National Academy of Sciences report.2 So it would seem that unless we eat more than three meals a day, the only way to ensure protein complementarity is to eat complementary proteins in the same meal.
In 1972, E. S. Nasset reported evidence of an “amino acid pool” that could make up for any deficiencies in the amino acid patterns of the food we eat. Nasset’s work has been cited by many to suggest that eating complementary proteins may be irrelevant. But most nutritionists disagree with Nasset. His amino acid pool theory “has been questioned by a number of workers and the results presented so far do not support Nasset’s theory,” reports a 1978 study.3 This view is confirmed by MIT’s Nevin Scrimshaw, a member of the group that sets the UN’s recommended protein allowances: “The Nasset Hypothesis is fallacious in that it applies only to the amino pattern in the intestine and not the overall amino acid turnover of the whole body.” Scrimshaw adds, “It is necessary to eat complementary protein within three to four hours.”4
Figure 16. Summary of Complementary Protein Relationships
In sum, then, here is what I have learned about protein in the last 10 years:
• To obtain more usable protein we don’t have to eat complementary proteins in the same meal, if we have frequent meals. But doing so seems to be convenient and easy, since so many dishes combine complementary proteins anyway.
• For effective protein use, however, we do need to eat complementary proteins within a few hours of each other.
• For most people, even those eating strictly a plant food diet, attention to complementary proteins is not necessary as long as the diet is healthy otherwise. Exceptions include pregnant and breast-feeding women; they must increase their protein more than their calories.
• No one should accept blindly the recommended protein allowances. Variations in protein need among individuals are so great that we must pay close attention to our need for more or less protein, observing both our overall sense of well-being and such danger signs as poor healing and unhealthy hair or nails.
• Presently available NPU ratings, such as those used in Appendix E to show the percentage of usable protein in foods, probably overestimate available protein. But since most people eat at levels above the recommended allowances, even without meat, this is generally no problem.
Part IV
Lessons for the Long Haul
1.
What Can We Do?
TO BE PART of building a more democratic society, one in which our economic structures are accountable to people’s needs, what can we do? Since we can’t take on the whole system at once, where can we start? How can we find others to work with, people who will not only help us accomplish our goals but also help us change ourselves?
I’ve found that food issues have a special ability to open doors. Everyone has an opinion about food, because everybody has to eat! But, as I have said, I’m not suggesting that everyone should become a food activist. Our society’s gravest problems have common