Navigation bar--use text links at bottom of page.

(Vegetarian Problem Scenarios--continued, Part B)

Why "failure to thrive" on vegetarian
diets is rarely talked about

When not everyone does well on the diet, the easy answers provided by the vegetarian movement are no longer so simple.

If you find yourself facing one of the six problem scenarios mentioned previously, you aren't alone--though you might not think so, given the positive press vegetarian nutrition often receives today. In fact, where health is concerned, most people do well, often quite well, on vegetarian diets when they first switch. (Certainly they usually do better, at least, if they had previously been following the "standard American diet"--often referred to as "SAD" by people pursuing healthier alternative diets.) And the positive press with respect to the long-term impact on certain degenerative diseases such as cardiovascular disease and so forth is well-deserved. Numerous studies have shown that diets higher in fiber, fruits, and vegetables and lower in saturated fats (such as vegetarianism, though it is not the only such diet, of course) are considerably healthier than the SAD when looking at certain degenerative diseases.

"Failure to thrive" is usually mild and unrecognized as such at first. However, there is another side to the vegetarian story that rarely gets talked about, which is the phenomenon known as "failure to thrive" (FTT). Normally this term is used to describe infants who fail to do well or to meet minimum standards for growth and development, due to some shortfall in the standard of care received. However, the term can also be applied to anyone not doing well health-wise when they might otherwise be expected to.

Where vegetarianism is concerned, it means that despite following prudent recommendations for the diet, some people simply do not experience the best health, or, put differently perhaps, "well-being." This can range anywhere from mild symptoms such as:

Prudent vegetarian diets are sufficient "on paper." Usually, since well-planned vegetarian diets are sufficient on paper, overt deficiencies are rare (other than of vitamin B-12 occasionally in pure vegans not taking a supplement). However, there is much that is still being discovered about nutrition, and--as is discussed elsewhere on the site--given that vegetarian diets are not the kind of diet that the human species evolved on, it may be there are dietary factors, particularly micronutrients, that don't measure up on diets that significantly deviate from our natural one. Or some elements in the diet may not be extracted as efficiently from plant foods, whether in general, or by certain individuals. (See Timeline of Dietary Shifts in the Human Line of Evolution for a footnoted discussion of dietary developments indicating the diet the human species is naturally adapted to. Also see Key Nutrients vis-a-vis Omnivorous Adaptation and Vegetarianism for a discussion of differences between plant and animal foods in absorption efficiency of certain dietary nutrients.)

But even allowing for the somewhat "covert" or subliminal nature of the above kinds of early or mild symptoms that might predispose people to believe FTT is not really real in the first place, what are the other reasons why FTT doesn't get talked about much? There are a few separate ones:

Failure to thrive is real, but its extent unknown.

After adopting the diet, cases of FTT are small in the beginning, but increase over the long-term. Now that the vegetarian and alternative diet movement has had almost three decades to mature since it began mushrooming in the U.S. with the contingent of baby-boomers who began adopting it starting in the late 1960s and early 1970s, results contrary to the standard healthy script of what is supposed to happen have had time to surface and undergo more close re-examination. Based on anecdotal reports, the number of people who experience FTT is small in the beginning after the diet is adopted, but will increase over time. Some begin not doing well within just a few months. For others it may be a decade or longer before they realize their state of health is not what it once was. Sometimes people find they have very slowly adjusted to a lowered sense of well-being without realizing it until some years later. It would be nice if one could put a percentage figure on the rate of FTT among those who try vegetarian diets, but unfortunately this number is unknown at present.

(Note: Vegan advocate Michael Klaper, M.D. has been attempting, since about 1997/1998, to put together what appears to be the first-ever study on failure to thrive in vegans, and also appears to be one of the very few vegan advocates to acknowledge it publicly as a worthwhile issue. It is a prospective study and not longitudinal, and thus will not be able to determine rates of incidence; but it is a start, and those who are interested in this topic may want to check out the web page for the study at

Most individuals with FTT make changes quietly, and go on to other diets. Some of these individuals who have had extensive firsthand experience from which they can speak have been forced to seriously question their diets--or at the least, the claim that they will work for everyone. And in some cases these individuals have even gone so far as to re-introduce animal foods back into their diets (some including carefully chosen portions of flesh) and are experiencing improved health. Others who haven't seen fit to make that kind of change may nevertheless have made compromises in the area of adding supplements or other auxiliary items to their diets formerly eschewed. (You can read stories of a few such individuals here on the website: see Dietary Problems in the Real World.)


(What Happens if Vegetarian Diets Are Not Best for Everyone?)

Return to beginning of article

Back to Frank Talk by Long-Time Insiders

   Beyond Veg home   |   Feedback   |   Links