I read this great blog post today which was written by a nutrition coach who has helped me (and many others) quite a bit over the years with my diet, performance, and aesthetics goals.  The post is pasted below in its entirety for your reading pleasure.  You can check out her practice here, and read some of her other posts which might be helpful for anyone looking to optimize his/her nutrition in an effort to achieve their specific goals.  You might recognize her. ;-)    

Good Food Bad Food - In Theory
I wish I could decouple the association of "good" and "bad" with foods.
I received this text from a client this morning.  So many of us grew up with this association, and it's a really hard habit to break, especially because "good" and "bad" foods are so often based on misguided or outdated assumptions that may not fit with our own views of what makes a food healthy or nutritious.
If we think of foods in terms of their underlying qualities, I think we can get somewhere useful in terms of breaking down these good/bad associations, and turn them into more useful assessments of whether to eat something.  How close is the food to its natural, unprocessed state?  Was the animal I'm eating healthy before I started eating it? Does this food give me adverse reactions like acne or a stomachache?  Does this food "fit my macros" or more broadly, "my goals"?
To be clear, food choices are very personal, and I realize some of the conclusions below may not be "fact" in some circles.  That said, my own beliefs summarize a great deal of experimentation and research into the ever-evolving knowledge base surrounding food and nutrition, so I clearly believe them to be valid.  If, by chance, something you read below doesn't resonate with you, I hope you'll reach out to me for some spirited debate (hopefully we'll both learn something!)
My methodology is strongly influenced by the great minds in the Paleo community, and I've become quite convinced that the research behind the recommendations to eat the highest quality food you can afford is sound.  Eating food that exposes us, either as it's growing or as additives in the final product, to chemicals, GMOs, altered fatty acid profiles, and other foreign influences relative to our more traditional food sources even a few hundred years ago, likely is a contributing factor to the maladies we as a society face today.  The more a food is processed, and the less natural the state in which it was raised (either plant or animal), the less likely it is to be a rich source of nutrients, and the more likely it is to be a rich source of toxins or antinutrients.
Assessing the possibility of food sensitivities, allergies and underlying autoimmunity is a popular concept on the internet these days, and not without basis.  For those sensitive to specific categories of foods: dairy, grains/gluten, legumes, nightshades, etc. these concerns are very real, and can be exceptionally disruptive to daily life and optimal function.  For these people (myself among them), choosing to eat foods which exacerbate your problems is a "bad" choice.  Not to say you can't make it, but in doing so, you are choosing to make yourself sick (still can be worth it occasionally).
Note: If you suspect you may have a food intolerance, and especially if you think you may have an underlying medical condition, I highly recommend seeking the advice of a professional who is interested in helping you assess the possibility in a responsible, medically sound way.  Once a food sensitivity or underlying medical condition is diagnosed (or ruled out), it's much easier and quicker to adjust your diet and lifestyle accordingly, rather than using blind self-experimentation to try to figure it out.  Some tests (like that for Celiac) are much less reliable once a particular food has been eliminated, so it's best to seek the advice of a doctor early on. 
Finally, energy balance (aka calories eaten relative to calories burned) is widely agreed to be a significant variable in the body composition equation. The tools for measuring calories eaten and calories burned are not as developed as most of us would like, and the body's mechanisms for adjusting metabolism to account for changes in energy balance are quite complex, but the underlying concept is useful.  Generally speaking, if you eat more than your body needs you gain weight, and if you eat less you lose weight.  A huge breakthrough in my understanding of good and bad food came years ago when I realized that there is actually a minimum intake required to support your body's basic functions like digestion, staying awake, rebuilding tissues, and breathing.  If you eat less than the amount required to support these basic functions, you won't lose weight as much as you'd think because your body down regulates your metabolism, essentially to save your life.  In this sense, calories are wonderful and necessary!  So many "bad" foods are considered bad simply because they are dense in calories (like the way I used to feel about avocado, if you can believe it), so it's important to factor this concept into your food assessments as well.  Generally speaking, how much do you need to eat per day in calories (the government recommends 2000-2500 for most people, and that's actually a pretty good estimate unless you're very small, large, active, or sedentary), and will you be satisfied throughout the day if you choose to eat this food as x% of your total intake? If yes, go for it!  If no, share it with a friend, or choose something else.  (If you're being more specific, the same goes for macronutrient breakdown - how much protein, carbs and fat do you need, and how much protein, carbs and fat does the particular food have).
In summary, developing an understanding of why you think a food is "good" or "bad" can be an extremely powerful tool in breaking these associations.  Some foods are more nutritious than others, some are more delicious than others.  Some actually make us sick, while others make us happy.  For most of us, it isn't even necessary to avoid "bad" foods (ones that actually are "bad" by the above criteria) all the time, we just need to avoid making them a habit to they point they could have a detrimental effect on our body composition or long-term health. 
At the risk of turning this into a full chapter, I'll end here for now.  In a later post, I plan to describe how to put this thinking into practice for assessing foods like hamburgers, milkshakes, and french fries (all of which have their carefully thought out place in my life).
-Triumph in The Arena

WOD for 04-07-16:

EMOM 7 Minutes:

2 Strict Press

Across

 

-then-

 

"The Kitchen Aid"

6 Rounds, Go Every 3 Minutes Alternating Between Run and Row:

400m Run | Row 25/20 Calorie Row

then

12 Toes-to-Bar

 

Score is your slowest time for any given round.