By Eric Trexler, CSCS, CISSN

Former Director of Research and Education, INOV8 Elite Performance

As an aspiring researcher in the field of exercise and nutrition, I’ve analyzed plenty of diet logs in my short career. Plugging meals into nutrition software isn’t the most exciting way to spend a few hours, but this menial task can teach you a lot about the way people eat. After analyzing a number of diets that would be considered “clean eaters” or “Paleo dieters,” I started to notice an interesting pattern.

What is “Clean”?

Before going forward, let’s establish a working definition for “clean.” The term itself is rather ambiguous and open to interpretation, but we all know the foods that are commonly considered clean. They’re the bodybuilding staples: Brown rice, sweet potatoes, oats, chicken breast, fish, vegetables (especially broccoli and asparagus), and so on. They tend to be foods with high micronutrient density and relatively low energy density. The carbohydrate sources tend to be complex, low on the glycemic index (which I believe to be largely unnecessary), and high in fiber. Refined carbohydrates and simple sugars are largely avoided by “clean eaters.” Common Paleo guidelines take this loose definition a step further, eliminating all dairy, cereal grains, and legumes.

The numerous “clean” diet logs I’ve analyzed have tended to be packed with micronutrients. In many cases, virtually all sources of “empty” calories were off limits; this is where the paradox part comes into play. After entering a number of “clean” diet logs into nutrition analysis software, I noticed a rather counterintuitive trend: These individuals, eating a diet almost exclusively composed of micronutrient-dense foods, were coming far short of the recommended intakes for a number of micronutrients. How could this be?

Inclusion dieting vs. Exclusion Dieting

If you stop by any bodybuilding-related forum or Facebook group, a war is raging on: “Clean” dieting vs. IIFYM (If It Fits Your Macros). A quick Google search will reveal thousands of forum arguments on the topic, but I’ll summarize it for any outsiders who are unfamiliar. The old-school, “clean” dieters advocate strictly sticking with clean foods (particularly the bodybuilding staple foods listed above). The IIFYM (also known as “flexible dieting”) crowd advocates a more flexible approach, allowing virtually any foods that fit within one’s target macronutrient intakes for the day.

I feel as if there are two ways to approach dieting— as you might have guessed from the bolded heading above, they are inclusion dieting and exclusion dieting. These approaches are characterized by distinctly different mindsets.

The inclusion dieter approaches food selection with the following mindset: “I will include food X in my diet, because it provides me with nutrients Y and Z.”

The exclusion dieter approaches food selection with a markedly different mindset: “I will exclude food X from my diet, because it hurts my dieting by providing Y and Z.”

One issue with the “exclusion” approach is its poor chances of long-term adherence. It forces you to decide that as long as you are dieting, you will avoid whatever “junk” foods you tend to crave (everybody has at least one— some, myself included, have several). As soon as you “break” and decide to satisfy that craving, you are officially off of your diet, which may cause you to binge, take a long-term break from dieting, or may lower your confidence in your own ability to successfully diet in the future.

Bringing it all together

In my opinion, diets focused on avoiding “bad foods” are inherently flawed. While there is certainly nothing wrong with the food sources they promote, their primary shortcoming is that they are predicated on exclusion dieting. Rather than selecting food choices that contribute the nutrients they need, these dieters focus more on avoiding things they perceive to be “bad.” The result is often superfluous intakes of some micronutrients, along with insufficient intakes of others. This explains “The Clean Foods Paradox,” and why a number of individuals may be eating micronutrient-dense foods all day and still falling short of recommended intakes for certain nutrients.

Having said that, I’m not letting the IIFYM/”flexible dieting” crowd off the hook without some criticism. This dietary approach should allow some flexibility in the choice of food sources, giving the dieter the freedom to choose foods that fit their preferences for taste and convenience. This should increase the dieter’s self-efficacy, along with increasing the chances of long-term diet adherence. Unfortunately, it sometimes seems as if flexible dieting has become a competition in which some (certainly not the majority) dieters try to fit as much ice cream and pop tarts into their diet as possible, often at the expense of fruits and vegetables (and the beneficial micronutrients and phytochemicals that come with them).


So what is the best way to diet? As is the case with most things in life, I believe moderation is key. When it comes to body composition, the most important factor of the diet (by far) is daily macronutrient intakes. My personal belief is that one should aim to satisfy their daily macronutrient targets (and their target for fiber intake) by choosing an overwhelming majority of micronutrient-dense foods, including plenty of fruits and vegetables. Although I sometimes take a multivitamin as a bit of “insurance,” I typically aim to achieve sufficient micronutrient intakes from my whole food sources.

While the majority of foods should be nutrient-dense, I also believe there is nothing wrong with including other foods that would typically be considered “junk food,” as long as micronutrient needs are met and the foods fit within your macronutrient targets for the day. Incorporating such foods in this context will not disrupt your diet in any way, and taking such an approach provides a much higher chance for long-term diet adherence.

So the take home point is to set appropriate macronutrient targets and use whatever foods you want to hit those targets, as long as daily micronutrient and fiber needs are met. For most people, satisfying these micronutrient and fiber requirements will demand that the majority of food choices will be “cleaner” food sources by default. Once micronutrient and fiber needs are met, knock yourselves out with the elaborate ice cream and pastry-laden concoctions.