Plant-based diets (from trusted sources) focus on foods derived from plants, including vegetarian and vegan eating patterns.
While vegan diets cut out all animal products, vegetarian diets—which only exclude meat and fish—are more varied and might include dairy and eggs. Pescatarian diets skip meat but still allow fish.
Plant-based diets are becoming more popular worldwide, thanks to years of scientific research and growing evidence (from trusted sources) highlighting their health benefits—like better blood cholesterol and blood sugar levels.
Plus, rising awareness of the environmental impact of raising animals—such as high greenhouse gas emissions, land damage, and heavy water use—has also encouraged (trusted source) some people to switch to plant-based diets, which tend to be more eco-friendly.
However, some plant-based diets come with health risks, especially if they include too many “junk” veggie foods.
What counts as “junk” plant-based foods?
By definition, ultra-processed foods (trusted source) are products with very little whole food content. They’re packed with calories, added sugar, salt, and fats, offer poor nutritional value, and are loaded with cheap industrial additives.
Using the NOVA classification system, which sorts foods based on how much processing they undergo, “junk” foods can include (trusted source) many plant-based items like:
- Store-bought bread, pastries, cakes, and cookies
- Sodas and fizzy drinks
- Packaged snacks
- Flavored dairy beverages
- Breakfast cereals
- Energy bars
- Instant sauces, soups, noodle pots, and desserts
Health risks
Ultra-processed foods are convenient and have taken over whole, minimally processed foods in many diets. In fact, they make up more than half (trusted source) of daily calorie intake for many people in middle- and high-income countries.
While a balanced plant-based diet is diverse, regularly eating ultra-processed plant-based foods is linked to negative health effects.
For example, a 2019 cohort study (trusted source) tracking 105,159 adults for five years found that even a 10% increase in ultra-processed food intake raised the risk of heart disease and stroke.
This small bump in ultra-processed foods is also tied to higher chances of certain cancers (trusted source), type 2 diabetes (trusted source), and exposure to harmful chemicals (trusted source) from food packaging.
On top of that, plant-based diets heavy in ultra-processed foods tend to be higher in calories, which can lead to weight gain (trusted source) and a greater risk of obesity (trusted source).
To make matters worse, vegetarian and vegan diets can cut out entire food groups, making nutrient deficiencies more likely.
Some studies suggest vegetarians and vegans often have lower levels (trusted source) of key nutrients like iron, vitamin B12, calcium, vitamin D, and omega-3 fatty acids.
A 2022 study (trusted source) also found that vegetarian women face a higher risk of hip fractures compared to women who eat meat occasionally.
These issues might be linked (trusted source) to skipping iron- and B12-rich meats and calcium-rich animal products without properly replacing them with fruits, vegetables, nuts, and pulses—especially if ultra-processed foods take their place.
How to avoid these health risks
Well-planned vegetarian or vegan diets offer plenty of health perks and can protect against nutrient gaps and the risks tied to ultra-processed plant-based foods.
Not only do plant-based diets support longevity (trusted source), but they may also help reduce age-related muscle loss (called sarcopenia) (trusted source) in older adults with obesity.
They’re also safe during pregnancy (trusted source) and breastfeeding—as long as nutrient needs are met—and even for athletic performance (trusted source).
Nutritionally balanced plant-based diets align better with U.S. dietary guidelines and improve overall diet quality (trusted source) based on the Healthy Eating Index.
This happens because they include more:
- Fruits
- Non-starchy vegetables
- Whole grains
- Low-fat dairy
- Eggs
- Plant protein
- Seafood
These diets also tend to be lower in salt, added sugar, fats, and calories.
So, not all plant-based diets are risky—but sticking to a healthy overall eating pattern is key to lowering the chances of heart disease, diabetes, and cancer.
How to eat a balanced plant-based diet
Here are some practical tips for keeping your plant-based diet varied and nutritious:
- Limit ultra-processed foods – Cut back on plant-based junk foods high in salt, sugar, and fats. Veggie meat substitutes, for example, are often packed with sodium and saturated fats, so opt for low-sodium, low-fat versions.
- Read nutrition labels (trusted source) – Don’t fall for flashy health claims on packaging. Check labels for sugar, salt, and fat content, and pick options with fewer additives. Labels can also help you spot foods richer in calcium and other key nutrients.
- Watch your carbs – Switching to plant-based eating might feel restrictive, and some people replace meat with refined or processed carbs. Stick to whole grains in portions that fit your health goals.
- Focus on protein – Load up on high-protein foods like beans, lentils, nuts, seeds, seitan, tofu, tempeh, edamame, eggs, dairy, yogurt, and seafood (for pescatarians). These also provide iron, calcium, vitamin D, and B12—nutrients often lacking in plant-based diets.
- Consider supplements – If needed, supplements can help fill nutrient gaps. Talk to your doctor or dietitian about which ones might work for you.
- Consult a dietitian – If you’re new to plant-based eating, a registered dietitian can help you plan meals that meet all your nutrient needs.
The takeaway
Plant-based diets are popular for good reason—they can boost heart health, blood sugar control, and lower the risk of diabetes, cancer, and obesity.
But “junk” veggie foods (ultra-processed options) make up a big chunk of many people’s diets and come with serious health risks.
Plus, vegetarians and vegans may struggle with deficiencies in iron, calcium, vitamin D, and B12 since they skip animal products rich in these nutrients.
That said, a well-planned plant-based diet—packed with fruits, veggies, whole grains, dairy (if included), and plant proteins—offers tons of benefits and helps avoid the pitfalls of processed “junk” foods.