Are Fruits and Veggies Really a Good Source of Fiber?

The message is everywhere—we should eat more fiber. The current Dietary Guidelines for Americans—the latest “food pyramid” concept—recommends that we consume 25 to 38 grams of fiber every day depending on age, gender and so on. Based on this sage advice, the average American manages to eat about half that amount. Why can’t (or won’t) we do better? One of the reasons might be that the most widely consumed produce items in the typical American diet has very little fiber, especially when you consider what fiber-rich items our not-so-distant ancestors had available.

The health benefits of fiber are well known. From regulating weight, lowering cholesterol, stabilizing blood glucose levels, and enhancing immune system, to good ol’ improved regularity, its hard to argue against increasing our consumption of fiber. (Click this link to read more about the health benefits of fiber and its role in promoting the health and well-being of our intestinal flora).

The USDA’s Economic Research Service keeps a snazzy little database on the amount of produce (veggies and fruit) that we grow and consume in this country. When you take into account the amount of produce lost during processing and due to spoilage, the amount that we actually consume is small. This meager amount is reduced further still when you consider how much is left on our plates or tossed from the refrigerator because it has wilted. The average American consumes only about 1.5 cups of vegetables and about a half cup of fruit per day. To put that in perspective, 16 grapes or 4 large strawberries equal a half cup. Not much.

Interestingly, the USDA data also reveal the lack of diversity in the fruits and veggies we consume. Even though there are tens of thousands of edible plants in our environment, Americans eat only about 30 or so vegetable products on a regular basis, and of these, a whopping five plants (potatoes, tomatoes, head lettuce, romaine/leaf lettuce, and onions) account for 66 percent of all veggies consumed. The top 10 plants account for 82 percent. It doesn’t take much research to discover our favorite vegetable in terms of consumption:  the potato. As for fruits; apples, bananas, grapes, strawberries, and oranges account for 63 percent of our consumption. (Note that tomatoes are technically a fruit because they contain seeds).

When you glance over the list of the top fruits and vegetables consumed by Americans, you immediately see the lack of diversity. You also see that, except for potatoes, the produce we eat is predominantly made up of water. This leaves very little “dry matter” or macronutrients such as protein, fat, and of course, fiber.

While we also get a portion of our fiber-fix from breads, pastas, and legumes/beans, there is a specific public health message to consume more fruits and veggies for a number of health reasons, much of it built on the assumption that these foods are also a good source of fiber. When viewed from an evolutionary perspective, our modern choices of which fruits and veggies we actually consume, preferences which are heavily influenced by geography, marketing, shelf life, and culinary, cultural and palate preferences, may not be an effective way to accumulate the quantity and diversity of fiber our bodies need. This lack of diversity is even more pronounced when you realize that the current recommendations for fiber intake are only a fraction of the 75 to 100 grams a day we should be consuming.

To illustrate the lack of fiber in among modern fruits and veggies, it’s useful to compare diets that are more in line with the nutritional landscape upon which we evolved a physiological need for fiber. The chart below shows the fiber content of the typical modern American diet compared to the intake of Australian Aborigines and Hadza foragers of northern Tanzania (who still live a non-westernized lifestyle), and detailed archaeological data from dry caves inhabited by hunter-gatherers for thousands of years in the Lower Pecos region of west Texas.

fiberavg2

The data presented above are for dry weights (water subtracted) and are displayed as grams of fiber per 100 grams of dry food weight (left axis). Using published nutritional data from 30 of the most popular veggies and 25 of the most consumed fruits in the American diet, we see that we get approximately 10.70 grams of fiber per 100 grams (about 3 ounces) of dry weight of produce consumed. When compared to fiber intake recorded at various places and times on the landscape represented by our three “ancestral or ancestral-like diets,” we have discordance. It’s interesting to note that the data displayed for the Australian Aborigines is derived from nutritional analyses of the 800-plus plants the Aborigines are known to consume.

Given our current choices of fruits and veggies consumed in America, we would need to double our consumption to meet the fiber levels present in plants that dominated our ancestral diet. Clearly, our current choices in plants is not going to result in any meaningful improvement in fiber consumption unless we increase our diversity to include plants with higher fiber content: high fiber legumes, beans, and tubers, for example.

With the issue of prevention moving slowly ahead of cure and management in our list of national healthcare priorities, any honest public health strategy will need to consider the underlying problems in the food supply. These issues go beyond the low hanging fruit of too many calories and too little exercise to a better understanding that while market forces and our own preferences shift our food supply, our evolutionary-determined needs are moving at a much, much slower pace. Eat more fiber.

**Each slice of NAKEDpizza delivers fiber from greater than 10 sources.

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One response to “Are Fruits and Veggies Really a Good Source of Fiber?

  1. I’m so glad I just finished a bowl of oat meal and ground flax seed right before I read this.

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