Scientific research has shown that flexible diets tend to outperform rigid ones (3,4,5). At the time of this writing, there are 2,435,856 posts under the hashtag IIFYM on Instagram. The slightly less popular #iifymgirls trails behind with just over 500,000 hashtags. (I would recommend starting here if you don’t know what IIFYM is.) Within the growing science-based fitness community a flexible approach has become universal and uncontroversial. If we imagine the current zeitgeist of the fitness community as a pendulum, I believe we have seen the pendulum swing from unanimous endorsement of meal plans and elimination diets to widespread exaltation of dietary flexibility. Flexibility is definitely good. In As You Like It Shakespeare asks us “why then, can one desire too much of a good thing?” It’s a good question. In this first blog post, I am going to offer 5 warning signs that you may be desiring too much of a good thing.

Your day has absolutely no structure.

Ghrelin is a hormone that regulates your hunger according to your meal patterning. If you’re used to eating lunch at 1pm, your body will start to let you know you’re hungry around noon, notifying you that it is soon time to eat. To put yourself in better control of your hunger, get into the habit of following some sort of structured eating pattern that works with your schedule – whether that be 3 square meals per day, 8 small meals per day or anything in between. The problem with a fully-freestyled approach to meal patterning is that hunger pangs can be random and sporadic or dull and constant and from my personal conversations with flexible dieters, such a lax approach seems to markedly increase the likelihood of breaking the diet and/or bingeing.

Ghrelin levels rise over the few hours preceding a meal and spike right before it to let you know it is time to eat.

You are eating foods that give you trouble.

So many adherents to a flexible dietary approach falsely assume that they can and should eat whatever they like. This leaves many folks consuming foods that give them GI distress, diarrhea, constipation or other lovelies. Interestingly, recent evidence points toward the idea that the symptoms seen from ostensible sufferers of so-called non-celiac gluten sensitivity (NCGS) may be attributable to a much more common condition called fructose malabsorption (FM). Apparently, as much as half of the entire planet could have FM, which might explain why so many people tend to get bloaty and gassy from eating breads (which are high in fructose in the form of fructans bound to gluten) and other high fructose foods (6). I personally feel awful after eating a big bag of candy (weird, hey?) The bottom line is that if you have consistently found a specific type of food to give you grief, then it would be wise to simply avoid these foods in spite of your new-found dietary flexibility.

You spend more time on myfitnesspal than you do eating your food.

If productivity is important to you, then a failure to pre-plan regular meals can turn into a major time-suck. Not only do you spend more time entering in each food individually, but you spend just as much time ruminating over what your next meal will be. An ability to find more structure and consistency in your eating patterns can free up both time and energy that can be better spent elsewhere. A simple suggestion would be copying and pasting set meals from previous days or using a meal inventory in your tracking app or spreadsheet. With structure comes the freedom to focus on the things you care about more.

You consume too many “empty calories”.

A 10-20% allotment of daily caloric intake as discretionary “free”/”junk” calories is a good figure to aim for. Err towards the lower end if you are on lower calories (<1500) and the higher end if you are on higher calories (>3000). While having this allotment in your diet is in essence what qualifies it as a flexible diet, the larger the bracket gets, the more likely you are to run into hunger-control problemsnutrient deficiencies, and dental caries (if a large portion of your free calories come in the form of sweets). Furthermore, research suggests that since foods higher in sugar have less satiating power, we should put a limit on these foods, lest we want to be hungry all the time (2).

You completely disregard nutrition around your workout.

I’ve noticed that a flippant attitude toward peri-workout nutrition seems to come part-in-parcel with a flexible dietary approach. I attribute most of this to a wonderful and very important paper that is often falsely touted as dismissing the value of post-workout nutrition. What the paper actually concludes is that “due to the transient anabolic impact of a protein-rich meal and its potential synergy with the trained state, pre- and post-exercise meals should not be separated by more than approximately 3–4 hours.” (1) Assuming a typical workout lasts an hour, and a typical pre workout meal is eaten 1-2 hours prior to training, this leaves a 0-2 hour window for the post-workout meal, depending on the length of the training session and the timing of the pre-workout meal. Even the co-author of the paper, Brad Schoenfeld, has stated that “for the average gym goer it isn’t going to make a difference, however if you are a bodybuilder or a strength athlete who needs every last morsel of muscle … at this point, without knowing otherwise, it is prudent to take in your protein quickly after the bout … within an hour or so.” While the specifics in terms of precise timing and dosing remain to be fully seen and we should always leave room for individual differences and personal preferences, dismissing the concept of peri-workout nutrition entirely, especially if you are a competitive athlete with physique or strength related goals, may be a sign that your flexibility pendulum has swung too far.

Final thoughts

To wrap it up, I’ll use an analogy. I thought of a few (braces, adjustable tripods, the human musculoskeletal system) but decided to go with bridges. The internet tells me that a good bridge has both flexible components (to allow for things like temperature-dependent expansion and contraction and forces like flexion) and rigid components to allow for things like structural integrity over time. I think a good diet should be set up like a bridge with flexible components and rigid components to strike up the best blend of adherence, long-term consistency and effectiveness.



1. Aragon AA, Schoenfeld BJ. Nutrient timing revisited: is there a post-exercise anabolic window?. J Int Soc Sports Nutr. 2013; 10(5)

2. de Ruyter JC, Katan MB, Kuijper LD, Liem DG, Olthof MR. The effect of sugar-free versus sugar-sweetened beverages on satiety, liking and wanting: an 18 month randomized double-blind trial in children. PLoS One 2013; 8(10): e78039.

3. Smith CF, Williamson DA, Bray GA, Ryan DH. Flexible vs. Rigid dieting strategies: relationship with adverse behavioral outcomes. Appetite 1999; 32(3)

4. Stewart TM, Williamson DA, White MA. Rigid vs. flexible dieting: association with eating disorder symptoms in nonobese women. Appetite 2002; 38(1): 39-44.

5. Timko CA, Perone J. Rigid and flexible control of eating behavior and their relationship to dieting status. Eat Weight Disord 2006; 11(3): e90-5.

6. Willett, Jennifer. How fructose malabsorption is a key factor in the condition known as “gluten intolerance”‘, Alan Aragon’s Research Review. December 2014: 12-15.

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