Variety is the Spice of Life: A “Healthy Diet” May Not Be Enough If You Lack Diversity

Eating healthy isn’t just about choosing “healthy” foods—it’s also about eating a wide variety of them. Many people settle into dietary routines that feel healthy—like the same smoothie, salad, or protein bowl every day—but without enough variety across and within food groups, even a well-intentioned diet can lead to nutrient gaps over time.

Each food offers a unique nutrient profile, and your body needs a broad spectrum of vitamins, minerals, amino acids, essential fats, phytonutrients, and antioxidants to function optimally. No single food (or food group) can supply everything your body needs. That’s why eating lots of different foods from each food group and within each food group is critical for optimizing health.

Even among health-conscious individuals, nutrient insufficiencies—levels too low to support optimal function but not low enough to cause clinical deficiency—are surprisingly common.

According to data from the NHANES (National Health and Nutrition Examination Survey) and the USDA Dietary Guidelines Advisory Committee:

• Over 90% of Americans fall short on at least one essential nutrient

• 75% do not get enough magnesium

• 70% are insufficient in vitamin D

• 60% fall short on vitamin E

• 50% or more do not meet requirements for calcium, vitamin A, and vitamin C

• Iron insufficiency is common, especially in women, affecting ~10%–20%

• Potassium intake is well below recommendations in almost all adults

Despite eating more total calories, athletes and physically active adults are also at risk—particularly due to increased demands and potential dietary restrictions:

• Up to 50% of athletes may have low vitamin D, depending on sport, season, and geographic location

• Iron deficiency affects ~35% of female athletes (and up to 80% in endurance athletes)

• Calcium and magnesium are often low in endurance or weight-conscious sports

• A study found more than half of collegiate athletes did not meet RDAs for vitamin E, potassium, and magnesium

Although a plant-based or vegan diet may yield good health outcomes, avoiding food groups (animal products) can increase the risk of deficiency for certain nutrients:

• Up to 92% of vegans are deficient in vitamin B12 without supplementation

• Vegans typically have lower iron and zinc levels, 30-50% below adequate levels

• Blood levels of EPA/DHA are 30–50% lower in vegans and vegetarians than in omnivores

• A study found that vegans had a 30% increased fracture risk compared to omnivores

• Another study found that 80% of vegans were iodine deficient in the U.S.

• A medical review found up to 75% of vegans were insufficient in vitamin D

Why Do We Need Variety?

The Nutritional Values of Different Foods: Each Food is Incomplete on Its Own

Every food provides a different set of nutrients. For example:

• Spinach is high in folate, vitamin K, and iron—but low in vitamin C and calcium

• Carrots provide beta-carotene (a vitamin A precursor) but lack vitamin D or magnesium

• Quinoa contains all essential amino acids but is low in certain minerals like calcium

• Salmon is rich in omega-3s and B12, but has minimal fiber or vitamin C

Relying too heavily on a handful of foods—even if they’re healthy—can inadvertently lead to micronutrient insufficiencies (not full-blown deficiencies, but suboptimal levels that affect energy, performance, immunity, and long-term health). We require balanced eating patterns to ensure we are getting a full range of nutrients.

The Absorption Factor: Nutrient Interactions

The combinations of foods you eat together also matters. Some food combinations promote absorption, while others can inhibit it—especially when it comes to minerals.

• Vitamin C + Iron: Vitamin C (in citrus, bell peppers, etc.) enhances absorption of iron from plant foods

• Healthy fats + Fat-soluble vitamins (A, D, E, K): These vitamins require dietary fat for absorption

• Zinc + Animal protein: Animal-based proteins enhance zinc bioavailability

• Phytates (in whole grains & legumes): Can bind to minerals like iron, calcium, and zinc, reducing absorption

• Oxalates (in spinach, beets, nuts): May inhibit calcium and magnesium absorption

• Polyphenols and tannins (in tea/coffee): Can reduce iron absorption if consumed with meals

• Calcium + Iron: Compete for absorption—best not taken together in supplement form or in back-to-back meals if optimizing both

• Zinc and copper: Also compete for absorption; high zinc supplementation can lead to copper deficiency.

This doesn’t mean you should avoid these foods—just that variety, rotation, and some strategic pairing can help ensure better nutrient availability over time. 

Other factors that can affect nutrient absorption include:

• Age: Nutrient absorption often declines with age (especially for B12, vitamin D, and calcium)

• Digestive health: Low stomach acid (hypochlorhydria), gut inflammation, or microbiome imbalance can reduce absorption of B12, iron, magnesium, and more

• Medications:

  • Antacids can reduce absorption of B12, magnesium, and calcium

  • Metformin may lower B12 and folate levels

  • Antibiotics can interfere with gut bacteria, affecting absorption and preventing vitamin K synthesis

• Alcohol: Chronic alcohol intake can impair absorption of folate, B vitamins, magnesium, and zinc

• Stress: Chronic stress can impair digestion, reduce enzyme output, and alter gut function, affecting nutrient absorption

Avoiding Food Groups: Increased Risk For Nutrient Gaps

While some people avoid certain food groups due to perceived health benefits, dietary preferences, tastes, allergies, intolerances, or for ethical reasons, doing so without awareness or planning can leave some void of necessary nutrients—even with an otherwise healthy diet.

For instance, some commonly avoided food groups & associated nutritional risks are listed below:

Dairy-Free Diets: Often avoided due to lactose intolerance, dairy protein sensitivity, plant-based preferences, or a fear of it causing health risks.

• Nutrient risk: calcium, vitamin D, riboflavin, iodine, B12

• Fortified plant milks help, but may not match the bioavailability or quantity in dairy

• Check your brands: some plant-based yogurts and cheeses have no added calcium or D

Grain-Free / Low-Carb Diets (e.g. keto, paleo): These diets often eliminate or greatly reduce whole grains and legumes.

• Nutrient risk: B vitamins (especially thiamin, folate, niacin), magnesium, selenium, iron, fiber, and antioxidants

• Reduced prebiotics (certain types of fiber) for the gut microbiome

Vegetarian or Vegan Diets: Highly beneficial when well-planned, but can lead to deficiencies when not monitored.

• Nutrient risk: vitamin B12, iron, zinc, calcium, iodine, omega-3s (EPA/DHA)

• May lack an adequate ratio of essential amino acids

• Plant-based sources of iron, calcium, and zinc are less bioavailable

• Requires intentional pairing (e.g., iron + vitamin C) and sometimes supplementation

Fat-Free or Very Low-Fat Diets: May be used for specific medical reasons but can lead to long-term issues.

• Nutrient risk: fat-soluble vitamins A, D, E, and K, omega-3 and omega-6 fatty acids

• Poor absorption of fat-soluble nutrients 

Avoiding All Animal Products (without substitutes): Even outside of full veganism, significantly reducing animal products can create gaps.

• Nutrient risk: creatine, carnitine, taurine, vitamin B12, heme iron, and vitamin K2

• These nutrients are either absent or present in non-bioavailable forms in plants

Benefits of Eating More Variety

Lower Risk of Nutrient Deficiencies - A 2020 review in the journal Nutrients found that individuals with low food variety were significantly more likely to fall short on essential nutrients like vitamins A, C, D, E, B12, folate, iron, magnesium, zinc, and fiber.

The more food groups and types of whole foods consumed, the more likely a person is to meet daily nutrient needs without supplements.

Reduced Risk of All-Cause Mortality - In a meta-analysis published in The British Journal of Nutrition, higher dietary diversity was linked to a significant reduction in all-cause mortality and cardiovascular-related deaths.

The benefits were strong when diversity came from plant-based whole foods, not ultra-processed foods.

Improved Gut Microbiome Diversity - A study from the American Gut Project found that people who consumed more than 30 different plant foods per week had significantly higher gut microbial diversity—a known marker of good health.

A diverse microbiome is associated with improved digestion, immunity, metabolism, and even mood regulation.

Improve Hunger and Satiety Signals - Higher variety in minimally processed, nutrient-dense foods improves satiety and long-term fat loss outcomes by supporting hormonal regulation, digestion, and fullness. In contrast, higher variety in ultra-processed or energy-dense foods may trigger appetite and promote fat gain.

Strategic variety in whole foods is ideal: rotate fruits, vegetables, proteins, legumes, and healthy fats to optimize satiety without triggering overeating.

Lower Risk of Obesity and Metabolic Syndrome - Variety—particularly in fruits, vegetables, legumes, and whole grains—has been associated with a lower body mass index (BMI), improved blood sugar regulation, and decreased risk of insulin resistance and type 2 diabetes.

Monotonous diets (even "healthy" ones) often lead to unintentional gaps in fiber, antioxidants, and micronutrients that regulate metabolic health.

Reduced Inflammation and Oxidative Stress - Different foods contain unique phytochemicals, polyphenols, and antioxidants that work synergistically to reduce systemic inflammation and oxidative damage—both key drivers of aging and chronic disease.

Colorful variety ("eat the rainbow") ensures coverage of a wide range of anti-inflammatory compounds.

Strategies to Improve Variety and Avoid Nutrient Insufficiencies

1. Rotate food choices weekly

• Try new grains (e.g., quinoa, farro, amaranth)

• Swap protein sources (e.g., fish, poultry, legumes, tofu, eggs)

• Rotate leafy greens (e.g., spinach, arugula, romaine, kale)

• Buy different color of produce every grocery trip

2. Eat the rainbow

• Aim for 5+ colors on your plate each day

• Different pigments = different antioxidants, fibers, and phytonutrients

3. Pair nutrients strategically

• Add citrus or bell pepper to iron-rich plant meals (e.g. dark leafy greens, beans, oats)

• Include healthy fats (avocado, nuts, olive oil) with vegetables

• Separate high-calcium and high-iron meals to optimize both

• Wait at least an hour after eating iron-rich foods before drinking tea or coffee, or vice versa.

4. Soak, sprout, or ferment plant foods

• Helps reduce phytate and oxalate levels, increasing mineral bioavailability

• Soak oats, lentils, or nuts overnight; soak quinoa before cooking; try sprouted grain breads or fermented foods like tempeh or miso

• Bonus: Supports gut health and digestion

5. Track or review your typical meals

• Use an app like Cronometer or MyFitnessPal to assess vitamin and mineral intake

• Even tracking for a few days can reveal patterns or gaps

6. Listen to your body

• Fatigue, poor recovery, cravings, mood or focus changes, trouble sleeping, numbness/tingling, brittle nails, or skin changes can signal micronutrient insufficiencies—even on a "healthy" diet

Try This Challenge: 

1. Eat at least 3 colors of vegetables or fruits each day

2. Swap one daily “habit food” (like your go-to breakfast or lunch) for a new version using different ingredients

3. Choose 1 new [unprocessed] food per week this month that you’ve never/rarely tried before

Make an intentional effort to pair foods, like adding a vitamin C food with iron-rich meals, add olive oil to veggie dishes, or avoid coffee/tea within an hour or two of an iron-rich meal