The 7 Foods Most Likely to Cause Weight Gain

For decades, you've heard that common diet foods such as whole grains, non-fat yogurt, and egg-white omelets are ideal for losing weight. The reality, however, is that these supposedly healthy foods might be the sneaky culprit behind your weight gain. 

Food sensitivities often play a hidden role in those extra pounds. When you repeatedly eat foods your body can't tolerate, it creates an immune response that can contribute to chronic inflammation. Long-term inflammation disrupts your hormonal balance, triggers insulin resistance, interferes with your digestive system, and causes fluid retention—a surefire formula for sabotaging your goals. 

You can be doing everything right, even eating healthy diet foods, and still not lose a pound. 

The 7 Hi-FI Foods 

Weight gain isn't the only consequence of food sensitivities. Other symptoms that directly or indirectly contribute to weight gain include bloating, fatigue, mental fog, irritable bowel syndrome, and cravings. Because these symptoms occur hours or even days after you eat the problem-causing foods, they can be hard to identify.¹ 

Eliminating foods your body can't tolerate and addressing chronic inflammation are the keys to finally finding your ideal weight. But how do you determine which foods to avoid? Drawing from my experience testing thousands of clients facing weight loss challenges, I've identified seven foods most likely cause food intolerance (aka Hi-FI foods) and stall weight loss. 

1. Gluten 

Gluten is a protein found in wheat, barley, rye, and their derivatives. It's responsible for the elastic texture of dough. Many grain-based foods like bread, pasta, and baked goods contain gluten (and there are many sneakier sources as well). An estimated 18 million Americans are sensitive to gluten.²  

You may have heard of Celiac disease, but this is distinct from gluten sensitivity. Celiac disease is an autoimmune disorder where eating triggers an immune response that damages the small intestine's lining and impairs nutrient absorption. Gluten sensitivity is a broader term encompassing people who experience adverse symptoms after consuming gluten-containing foods but don't have an autoimmune response. 

In my practice, about 90% of clients who removed it felt much better. And I was convinced those who didn't feel better weren't completely pulling gluten out. Symptoms of gluten sensitivities include abdominal pain, bloating, diarrhea, and non-gastrointestinal issues like headaches, fatigue, and joint pain.³ 

Gluten-containing foods can also cause weight gain by disrupting blood-sugar balance and contributing to insulin resistance.⁴ This protein can also potentially harm the integrity of tight junctions within your intestinal lining, increasing the risk of developing a condition called leaky gut.⁵ 

With leaky gut, you’re not absorbing nutrients as well as you should, potentially leading to more intense food cravings and stalling your weight-loss efforts. Gluten-induced leaky gut can also trigger inflammation, opening the door to autoimmune disorders and other health challenges.⁶ 

Research shows that a well-designed gluten-free diet can help reduce chronic inflammation and insulin resistance while helping you reach your ideal weight.⁷ When I say well-designed, I'm not talking about gluten-free cookies, breads, and muffins. Gluten-free does not necessarily mean healthy—and it definitely does not always mean good for weight loss. 

2. Dairy 

The U.S. food system has long touted dairy's supposed health benefits, particularly for building strong bones. However, there's more to the story. 

About 75% of the world’s population cannot digest lactose, the primary sugar in dairy.⁸ When lactose-intolerant people consume dairy, the undigested sugar travels to the colon and becomes a food source for harmful gut bacteria. This can disrupt the balance between good and bad bacteria in the gut, leading to various health issues that impact the digestive system, the immune system, mental health, and skin health. 

Dairy products can be problematic for some people for reasons beyond lactose intolerance. One significant issue is related to the proteins found in dairy, primarily casein and whey. They can contribute to skin problems like acne, eczema, rosacea, and dermatitis.⁹  

Other symptoms may include nausea, stomach cramping, gas, bloating, diarrhea, constipation, joint pain, headaches, and fatigue. Some forms of dairy can even cause flare-ups of certain autoimmune conditions.¹⁰ 

Some people do well with grass-fed dairy, including Greek yogurt. For these folks, dairy can be a good source of protein. For others, dairy is off-limits. As I explain in The Virgin Diet, the only way to know is to eliminate dairy for a few weeks and then bring it back in to test how you feel. 

Even for those who can tolerate dairy, it's worth noting that it can still play a significant role in weight gain. One glass of milk can spike insulin levels by 300%, contributing to obesity and elevating the risk of developing insulin resistance. ¹¹  

3. Soy 

Soy is relatively new in our food supply, with a history of consumption spanning less than 1,000 years. Many soy products are heavily processed, which can strip them of essential nutrients. Additionally, a significant amount of soy is genetically modified (GMO).¹²  

Among its problems, soy contains goitrogens, compounds that can interfere with thyroid function, potentially leading to hypothyroidism or triggering autoimmune conditions like Hashimoto's thyroiditis.¹³ Your thyroid regulates your body's metabolic rate, influencing how efficiently it burns calories for energy. Alterations in thyroid hormone levels (such as with hypothyroidism and Hashimoto's) can lead to weight fluctuations. 

Soy processing often involves using aluminum casks, which can result in contamination. Excessive aluminum exposure can be a health concern for dementia and other issues.¹⁴ Soy also contains phytates, which can bind to essential minerals like calcium, magnesium, copper, iron, and zinc, hindering their absorption and potentially causing deficiencies.¹⁵ 

Soy contains phytoestrogens that can mimic the hormone estrogen in the body, affecting hormonal balance and potentially lowering testosterone levels or impacting fertility (particularly in women of reproductive age).¹⁶ Researchers have also linked processed soy with adverse effects on brain development in children, brain shrinkage in men, and dementia in both genders.¹⁷  

4. Eggs 

Eggs are a great source of protein, fat, and other important nutrients. I used to love them so much that I ate them every day. I think they are one of nature’s perfect foods. 

When I started doing food-sensitivity testing, I found eggs repeatedly showed up in the results. For some clients, symptoms included gas, bloating, and heartburn. Others found that skin problems like eczema and psoriasis worsened. Many struggled to lose weight. Those are signs that you’re intolerant to eggs. 

One major issue involves a chicken’s diet. When farmers feed chickens GMO corn and soy, they aren’t going to produce high-quality eggs. Remember, what you eat is influenced by what the animal ate. Corn or soy can alter the fatty-acid composition of the eggs chickens lay. When chickens are fed corn, their eggs tend to be higher in arachidonic acid, which can promote the inflammation that contributes to weight gain.¹⁸ 

Be wary of grocery-store labels. Organic usually means the chickens are fed organic soy and corn, which isn’t really any better. And free-range means that chickens are given the option to roam freely, not necessarily that they do.  

Some people find that they do well eating pasture-raised eggs. Their eggs have a more balanced profile of fats, more vitamin D, and a higher omega-3 content. Other people don’t do well with eggs at all. If that’s you, you have lots of other protein sources including grass-fed beef and wild-caught seafood. 

Every meal should contain protein first. That means you're getting 30-50 grams of protein every time you eat. Don’t guess how much you’re getting! My Protein Cheat Sheet provides a list of foods containing 30-60 grams of protein to make it super easy, and you can download it for free. 

5. Corn 

Corn is an inflammatory food that also causes your blood sugar to spike—a double whammy for weight gain. It’s one of our most genetically modified foods, too. Corn sensitivities can manifest in various symptoms, including:  

• Rashes 
• Hives 
• Migraines 
• Joint pain 
• Mood disorders 
• Temporary depression 
• Insomnia 
• Eczema 
• Fatigue 
• Ongoing sinus problems¹⁹ 

According to Peter Osborne, DC, corn has a form of gluten called zeins. Dr. Osborne says that corn gluten is as inflammatory as wheat. It can cause gut inflammation in patients with gluten sensitivity, celiac disease, ulcerative colitis, and Crohn’s disease—even GMO-free corn that had no cross-contamination ²⁰ 

Corn is everywhere: cornstarch, corn syrup, corn oil, and high-fructose corn syrup. Even if you’re not eating corn, you might be eating corn-fed beef or chicken. That's why you always want to choose pasture-raised chicken fed their natural diet and grass-fed beef. 

6. Peanuts 

For many people, peanuts (and peanut butter) can create symptoms like bloating, gas, indigestion, fatigue, mental fog, irritability, moodiness, and weight gain. Peanuts have a high risk of containing aflatoxins, toxins that may contribute to allergies, liver cancer, and impaired immune function.²¹ 

Conventional peanut farming often involves the heavy use of pesticides, making peanuts susceptible to pesticide residues.²² Peanuts also contain anti-nutrients like phytic acid and lectins, which can disrupt gut function, cause inflammation, and hinder nutrient absorption.²³ 

Moreover, many commercial peanuts contain added sugars, vegetable oils, and other problem ingredients. One brand of innocent-sounding sea salt dry roasted peanuts has the following ingredients: 

Ingredients: Peanuts, Sugar, Contains 2% Or Less Of The Following: Sea Salt, Yeast Extract, Modified Corn Starch, Corn Starch, Torula Yeast, Molasses, Spice, Onion Powder, Garlic Powder, Natural Smoke Flavor. Oleoresin Of Paprika (contains Soybean Oil). 

Sugar is the second ingredient! Then there's corn starch, molasses (sugar), and soybean oil. Commercial peanut butter is equally bad, containing added sugars and hydrogenated oils.  

Fortunately, almonds and other tree nuts (as well as their butters) are an easy swap for peanuts. 

7. Sugar and Artificial Sweeteners 

Sugar can harm your health and hinder your weight loss in several ways. Eating high-sugar-impact foods creates significant fluctuations in blood-sugar levels, potentially leading to insulin resistance, fatty liver, and other related issues.²⁴ 

Sugar can also decrease your intake of essential vitamins, minerals, and other nutrients. According to Vincent Pedre, MD, sugar contributes to chronic inflammation, creates a higher risk of some diseases including cancer, and negatively impacts your cholesterol. Plus, sugar is highly addictive. The dopamine release it triggers in your brain makes eating sweets feel rewarding.²⁵ 

As I discussed in Sugar Impact Diet, not all sugars are equal. There, I showed how the impact of the food is what matters most. You don't have to go cold turkey. However, you must choose your sugar wisely.  

In the book, I discuss the most significant sources of hidden or sneaky sugars in places you would never suspect, how to gradually identify sugar from seven food groups, gradually reduce your intake, and reset and retrain your taste buds. 

Artificial sweeteners aren't any better. Despite their zero or near-zero-calorie content, research has linked artificial sweeteners to a range of issues, including headaches, cardiovascular problems, and chronic kidney disease.²⁶ 

Some studies find that artificial sweeteners may interfere with your body's ability to regulate calorie intake, making you eat more than you should and increasing cravings.²⁷ 

Artificial sweeteners may also:  

• Raise insulin levels²⁸ 
• Negatively impact gut health²⁹ 
• Disrupt mood by affecting neurotransmitters like serotonin³⁰ 

Those are among the reasons why, despite their “diet” reputation, artificial sweeteners may actually contribute to weight gain.³¹ 

Let Go of the Foods That Are Hurting You and Making You Gain Weight 

Weight gain and symptoms like bloating and fatigue are your body's way of telling you that you're eating foods that aren't working for you. You'll likely struggle with weight loss until you eliminate the foods your body can't handle.   

During my early days working with clients, I learned the same foods were showing up repeatedly. These seven foods were stalling their progress and holding their weight (and health) hostage. When we pulled these foods for at least 21 days, everything shifted. They looked and felt better… and the weight finally came off.  

From those discoveries, I created The Virgin Diet. This program provides all resources to help calm inflammation from hidden food sensitivities, lose fat, reclaim your health, and feel energized.  

References: 

1. Pedre, Vincent. Happy Gut (p. 155). HarperCollins. Kindle Edition. 

2. RN.com: Gluten: It’s Not for Everyone 

3. Healthline: 21 Common Signs of Gluten Intolerance 

4. Haupt-Jorgensen M, Holm LJ, Josefsen K, Buschard K. Possible Prevention of Diabetes with a Gluten-Free Diet. Nutrients. 2018 Nov 13;10(11):1746. doi: 10.3390/nu10111746. PMID: 30428550; PMCID: PMC6266002. 

5. Healthline: Does Gluten Cause Leaky Gut Syndrome? 

6. Paray BA, Albeshr MF, Jan AT, Rather IA. Leaky Gut and Autoimmunity: An Intricate Balance in Individuals Health and the Diseased State. Int J Mol Sci. 2020 Dec 21;21(24):9770. doi: 10.3390/ijms21249770. PMID: 33371435; PMCID: PMC7767453. 

7. Soares FL, de Oliveira Matoso R, Teixeira LG, Menezes Z, Pereira SS, Alves AC, Batista NV, de Faria AM, Cara DC, Ferreira AV, Alvarez-Leite JI. Gluten-free diet reduces adiposity, inflammation and insulin resistance associated with the induction of PPAR-alpha and PPAR-gamma expression. J Nutr Biochem. 2013 Jun;24(6):1105-11. doi: 10.1016/j.jnutbio.2012.08.009. Epub 2012 Dec 17. PMID: 23253599. 

8. Mattar R, de Campos Mazo DF, Carrilho FJ. Lactose intolerance: diagnosis, genetic, and clinical factors. Clin Exp Gastroenterol. 2012;5:113-21. doi: 10.2147/CEG.S32368. Epub 2012 Jul 5. PMID: 22826639; PMCID: PMC3401057. 

9. The Times of India: Why do skin experts advise against dairy products 

10. Science and Education Publishing: Bovine Milk Proteins as a Trigger for Autoimmune Disease 

11. Hyman, Mark. The Blood Sugar Solution: The UltraHealthy Program for Losing Weight, Preventing Disease, and Feeling Great Now! (p. 208). Little, Brown and Company. Kindle Edition. 

12. Western Kentucky University: Is Soy Healthy or Harmful? 

13. Thyroid Pharmacist: How Goitrogens Affect Hashimoto's 

14. Alasfar RH, Isaifan RJ. Aluminum environmental pollution: the silent killer. Environ Sci Pollut Res Int. 2021 Sep;28(33):44587-44597. doi: 10.1007/s11356-021-14700-0. Epub 2021 Jul 1. PMID: 34196863; PMCID: PMC8364537. 

15. Today’s Dietician: Soy Antinutrients 

16. Kaayla T. Daniel: The Whole Soy Story: The Dark Side of America's Favorite Health Food. Newtrends Publishing, Inc. (March 10, 2005). 

17. Guo C, Wilkens LR, Maskarinec G, Murphy S. Examining associations of brain aging with midlife tofu consumption. J Am Coll Nutr. 2000 Aug;19(4):467-8. doi: 10.1080/07315724.2000.10718948. PMID: 10963466. 

18. Tallima H, El Ridi R. Arachidonic acid: Physiological roles and potential health benefits – A review. J Adv Res. 2017 Nov 24;11:33-41. doi: 10.1016/j.jare.2017.11.004. PMID: 30034874; PMCID: PMC6052655. 

19. ShareCare: What Are The Symptoms Of A Food Sensitivity To Corn? 

20. High Intensity Health: The Hidden Glutens in Corn, Rice and Soy 

21. National Cancer Institute: Aflatoxins – Cancer-Causing Substances 

22. FoodPrint: Real Food Encyclopedia – Peanuts 

23. Pathaw N, Devi KS, Sapam R, Sanasam J, Monteshori S, Phurailatpam S, Devi HC, Chanu WT, Wangkhem B, Mangang NL. A comparative review on the anti-nutritional factors of herbal tea concoctions and their reduction strategies. Front Nutr. 2022 Oct 5;9:988964. doi: 10.3389/fnut.2022.988964. PMID: 36276812; PMCID: PMC9581206. 

24. Harvard T.H. Chan School of Public Health: Carbohydrates and Blood Sugar 

25. Pedre, Vincent. Happy Gut (pp. 43-44). HarperCollins. Kindle Edition. 

26. Sharma A, Amarnath S, Thulasimani M, Ramaswamy S. Artificial sweeteners as a sugar substitute: Are they really safe? Indian J Pharmacol. 2016 May-Jun;48(3):237-40. doi: 10.4103/0253-7613.182888. PMID: 27298490; PMCID: PMC4899993. 

27. Purdue University: Artificial sweetener may disrupt body's ability to count calories 

28. Healthline: Do Artificial Sweeteners Spike Your Blood Sugar? 

29. The Scientist: Artificial Sweeteners Alter Gut Bacteria in Humans 

30. Health News: Link Between Artificial Sweeteners and Depression 

31. Yang Q. Gain weight by “going diet?” Artificial sweeteners and the neurobiology of sugar cravings: Neuroscience 2010. Yale J Biol Med. 2010 Jun;83(2):101-8. PMID: 20589192; PMCID: PMC2892765. 

The views in this blog by JJ Virgin should never be used as a substitute for professional medical advice. Please work with a healthcare practitioner concerning any medical problem or concern. The information here is not intended to diagnose, treat, or prevent any disease or condition. Statements contained here have not been evaluated by the Food and Drug Administration.