Keto. Paleo. Vegan. Vegetarian. Gluten-free, dairy-free, low-carb, carnivore… the list goes on. 

With all of the pop diets out there these days, how do you know which ones are healthy and would suit you?

Through this blog series, we’ll teach you how to evaluate diets based on science – no matter what your favorite influencer says about it. 

We recommend starting at part one, but here’s a recap. When evaluating diets, you’ll want to check on a few different characteristics, including:

  • Fiber intake
  • Polyphenol content
  • Probiotic / fermented food content
  • Electrolyte intake
  • Processed food content
  • Micronutrient intake
  • Caloric intake
  • Fat, protein, and carbohydrate intake
  • Gluten, dairy, or sugar intake: other triggers
  • Price 
  • Sustainability 
  • Adherence / lifestyle match

That sounds like a lot – but tracking these criteria is much simpler than it sounds. 

Let’s jump in! Today, we’ll look at processed food intake.

Processed Food Content

One of the most relevant features of diets is their processed food inclusion or exclusion. That’s because processed foods are typically bad for you (1).

Processed foods negatively impact:

  • Cognition (2)
  • The gut microbiome (3)
  • Gut barrier integrity (4)
  • Motility (5)
  • Blood lipids (6)
  • Heart health (6)
  • The immune system (7)
  • Inflammation levels (7)

One study showed that for every 10% of your daily calories that come from processed foods, your risk of death increases by 14% (8). Now that’s a finding to consider.

Processed foods often contain additives and toxins like BPA and pesticides that are adverse to our health (9).

Another problem with processed foods is their upregulation of energy balance and lack of nutrient density. You might be thinking – what do these terms mean again?

Energy balance refers to the ratio between the energy you take in through food and the energy you expend through activity. You want these to stay even.

If you eat more than you need based on your activity level, your energy balance is imbalanced, and you will likely gain weight. If you eat less than you need based on your activity, your energy balance is imbalanced, and you will probably lose weight.

Processed foods are packed with excessive calories – and their composition makes it difficult for your body to realize you’ve had enough.  

Emulsifiers that are often added to these foods (like soy lecithin) are proven to downregulate nutrient detection (your body’s ability to know when you’ve had enough food) (10).

That means that too much consumption of processed foods will likely throw your energy balance off (and send you into metabolic chaos).

They are also low in nutrient density. Nutrient density refers to the ratio of nutrients to calories in a food. You want high nutrient density foods – meaning the food provides lots of nutrients per calorie. 

High-calorie, nutrient-dense foods, like avocadoes, are worth it because you get bang for your buck. There are lots of nutrients per small amount of avocado. 

On the other hand, Cheetos are high-calorie but do not contain many nutrients. They are an example of a food with low nutrient density.

Processed foods are typically high-calorie and provide very few nutrients – providing the opposite of what a healthy diet supplies the body.

Nutrition gurus from all camps typically agree that ultra-processed foods are problematic. So when evaluating a new diet, consider its emphasis or limitation of processed foods.

You may consider putting a whole-food spin on your diet of choice – for example, if you’re thinking of going vegetarian, you can limit the processed foods you include.

Continue reading the rest of the blog series to learn about other diet criteria. Tag us in photos of your meals on Instagram @igynutrition. Thanks! 


  1. Pagliai G, Dinu M, Madarena MP, Bonaccio M, Iacoviello L, Sofi F. Consumption of ultra-processed foods and health status: a systematic review and meta-analysis. Br J Nutr. 2021 Feb 14;125(3):308-318. doi: 10.1017/S0007114520002688. Epub 2020 Aug 14. PMID: 32792031; PMCID: PMC7844609. 
  2. Torres, Susan J et al. “Dietary patterns are associated with cognition among older people with mild cognitive impairment.” Nutrients vol. 4,11 1542-51. 25 Oct. 2012, doi:10.3390/nu4111542 
  3. Miclotte L, Van de Wiele T. Food processing, gut microbiota and the globesity problem. Crit Rev Food Sci Nutr. 2020;60(11):1769-1782. doi: 10.1080/10408398.2019.1596878. Epub 2019 Apr 4. PMID: 30945554. 
  4. Snelson M, Tan SM, Clarke RE, de Pasquale C, Thallas-Bonke V, Nguyen TV, Penfold SA, Harcourt BE, Sourris KC, Lindblom RS, Ziemann M, Steer D, El-Osta A, Davies MJ, Donnellan L, Deo P, Kellow NJ, Cooper ME, Woodruff TM, Mackay CR, Forbes JM, Coughlan MT. Processed foods drive intestinal barrier permeability and microvascular diseases. Sci Adv. 2021 Mar 31;7(14):eabe4841. doi: 10.1126/sciadv.abe4841. PMID: 33789895; PMCID: PMC8011970.,that%20leads%20to%20chronic%20disease
  5. Schnabel L, Buscail C, Sabate JM, Bouchoucha M, Kesse-Guyot E, Allès B, Touvier M, Monteiro CA, Hercberg S, Benamouzig R, Julia C. Association Between Ultra-Processed Food Consumption and Functional Gastrointestinal Disorders: Results From the French NutriNet-Santé Cohort. Am J Gastroenterol. 2018 Aug;113(8):1217-1228. doi: 10.1038/s41395-018-0137-1. Epub 2018 Jun 15. PMID: 29904158. 
  6. Leffa PS, Hoffman DJ, Rauber F, Sangalli CN, Valmórbida JL, Vitolo MR. Longitudinal associations between ultra-processed foods and blood lipids in childhood. Br J Nutr. 2020 Aug 14;124(3):341-348. doi: 10.1017/S0007114520001233. Epub 2020 Apr 6. PMID: 32248849. 
  7. Childs, Caroline E et al. “Diet and Immune Function.” Nutrients vol. 11,8 1933. 16 Aug. 2019, doi:10.3390/nu11081933 
  8. Schnabel L, Kesse-Guyot E, Allès B, et al. Association Between Ultraprocessed Food Consumption and Risk of Mortality Among Middle-aged Adults in France. JAMA Intern Med. 2019;179(4):490–498. doi:10.1001/jamainternmed.2018.7289 
  9. Simmons, Amber L et al. “What Are We Putting in Our Food That Is Making Us Fat? Food Additives, Contaminants, and Other Putative Contributors to Obesity.” Current obesity reports vol. 3,2 (2014): 273-85. doi:10.1007/s13679-014-0094-y 
  10. Chassaing, B., Koren, O., Goodrich, J. et al. Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome. Nature 519, 92–96 (2015).