Are some vegetables unhealthy and other vegetables healthy?

Based on the so-called “5-a-day” rule, if a person eats at least five fruits and/or vegetables a day, that person will enjoy a good level of health.

On the other hand, and according to findings that resulted from scientific research, consuming certain vegetables, such as corn, potatoes, and peas, can harm a person’s health, rather than boosting it.

Where does the truth lie, and which one of these seemingly contradictory statements should people believe?

Like most things in life, there is not a clear “yes or no” answer to whether vegetables are good to eat, or not.

For example, a person with other unhealthy habits in their life, but who also consumes five fruits and vegetables a day, will not find much benefit in eating fruits and vegetables, unless they also change their lifestyle radically.

The adoption of healthy eating habits can be a good starting point. However, a person needs to follow a balanced lifestyle in other areas, as well.

Not all types of diets are suitable for everyone

Let’s take the example of an athlete.

If an athlete stops consuming carbohydrates, their performance will be negatively affected, due to lack of energy.

Therefore, the results of scientific research leading to the conclusion that certain vegetables, which contain a high level of carbohydrates in the form of starch, like corn or potatoes, can be harmful, would not apply to athletes with high energy needs.

Or, they could apply, but to a much less extent than to people who lead a sedentary lifestyle.

Too much of a good thing can be bad

With the exception of those people who detest the idea of changing their unhealthy eating habits, unless their doctor gives them only a few months to live, it is generally believed today, that eating greens, for example, can shield a person’s health and help them live more.

Can a person live only on greens, though?

If that was the case, then humans would have a ruminant digestive system, but they don’t.

Again, a person can enjoy a healthy life by practicing moderation in all things and following a balanced diet, rather than choosing to consume one type of food over another based on their allegedly different levels of health benefits.

I can’t imagine how a marathon runner could finish a race without a big intake of carbohydrates, which could be taken from corn, potatoes, or peas, for example.

On the other extreme, even an athlete would find it hard to live only on starchy vegetables, since the human body needs all types of nutrients to function properly, and therefore, vegetables containing very little carbohydrate but very high fiber levels would also be highly beneficial.

Scientific research on food is very context-specific

I tend to believe that there can be limitations, not to say flaws, in scientific research, even if it comes from highly respected academic institutions.

When researchers define their sample, they try to make it as representative of the general population as possible.

When it comes to the general population, however, there is no behavior that can be characterized as “normal”, i.e. typical of the “average person”, because there are no such things as “normal behavior” and “average person”.

Everyone is different, and therefore, when researchers focus on a sample, even if that sample is representative of the population, the conclusions that will be drawn from research may not necessarily apply to all people in the population to the same degree.

If you have someone who is tall and someone else who is short, their average height does not represent them, because these two extremes will continue to exist, in spite of the effort to average the difference.

In case of research on how healthy vegetables really are, the research sample will inevitably include a specific proportion of healthy people and people with a disease, and this proportion will reflect the actual makeup of the population.

However, it is not possible or sensible to take a healthy person and a person who suffers from a disease and average them to get a person with a medium level of health.

For the same reason, it does not make any sense to generalize research results over very different groups of the general population, and that is the reason why I question the interpretation of the specific research results, which cannot and should not be generalized, in my opinion.

Sources and further reading:

This is the unhealthiest vegetable you can eat

Can vegetables cause digestive issues?

The Nutrition Source-Vegetables and fruits

The 14 healthiest vegetables on Earth

The 14 Most Nutrient-Dense Vegetables

What are the most healthful vegetables?