A vegan diet can meaningfully lower your risk of heart disease, type 2 diabetes, and certain cancers, while cutting your personal carbon footprint by up to 2.1 tons per year. Those are the two big categories of reasons: your health and the planet’s health. The strength of the case depends on how you approach it, because a poorly planned vegan diet can backfire on both fronts.
Heart Disease Risk Drops Significantly
Heart disease is the leading cause of death worldwide, and diet is one of the biggest modifiable risk factors. A large study published in the Journal of the American Heart Association found that people with the highest adherence to a plant-based diet had a 16% lower risk of developing cardiovascular disease, a 31% to 32% lower risk of dying from it, and an 18% to 25% lower risk of dying from any cause compared to those who ate the least plants.
The mechanisms are well understood. Plant-heavy eating patterns lower blood pressure, reduce LDL cholesterol (the kind that clogs arteries), decrease inflammation, and improve blood sugar control. These aren’t small, speculative effects. They’re the same targets that doctors focus on when prescribing statins and blood pressure medications, achieved partly through food instead.
Better Blood Sugar Control
For people with type 2 diabetes, a vegan or vegetarian diet reduces hemoglobin A1c (the standard measure of average blood sugar over three months) by about 0.4 percentage points compared to conventional diets. That may sound modest, but in diabetes management, a 0.4% reduction in A1c is clinically meaningful. It’s comparable to what some oral diabetes medications achieve.
The reason is straightforward. Whole plant foods tend to be high in fiber and low on the glycemic index, meaning they release sugar into your bloodstream more gradually. Legumes, whole grains, vegetables, and nuts all help your body use insulin more efficiently. If you’re at risk for type 2 diabetes or already managing it, shifting toward plant-based eating is one of the most effective dietary changes you can make.
Lower Colorectal Cancer Risk
A meta-analysis of prospective studies involving over 3 million participants found that plant-based dietary patterns reduced the risk of digestive tract cancers by 12% to 24%. For colorectal cancer specifically, the overall risk reduction was about 9%, but that number improved when people emphasized healthy plant foods like fruits, vegetables, whole grains, legumes, and nuts rather than refined grains and sugary processed foods.
One U.S. cohort study illustrates this distinction sharply: a healthy plant-based diet was associated with a 28% reduction in colorectal cancer risk, while an unhealthy plant-based diet (think white bread, fries, and soda, all technically vegan) was linked to a 41% increase in risk. Going vegan isn’t automatically protective. The quality of what you eat matters enormously.
The Environmental Case
If the entire world adopted a vegan diet, global agricultural land use would shrink from 4.1 billion hectares to 1 billion hectares, a reduction of 75%. That’s according to data compiled by Our World in Data from Oxford University research. Most of the land currently used for agriculture goes toward raising livestock or growing feed crops for animals, not growing food that humans eat directly.
On an individual level, switching to a vegan diet can reduce your annual carbon footprint by up to 2.1 tons of CO2 equivalent, according to the United Nations. For context, that’s roughly the emissions produced by driving 5,000 miles in an average car. A vegetarian diet gets you partway there, cutting about 1.5 tons. The difference between the two comes largely from dairy production, which requires significant land, water, and energy.
The freed-up land isn’t a trivial detail. Restoring even a fraction of that acreage to forests, wetlands, or grasslands would create massive carbon sinks and help protect biodiversity. Animal agriculture is one of the primary drivers of deforestation in the Amazon and habitat loss globally.
Nutrients You Need to Plan For
Vitamin B12 is the non-negotiable supplement for vegans. Your body can’t make it, plants don’t reliably provide it, and a deficiency causes real damage. B12 protects the sheath around your nerves, so running low can cause numbness, tingling, balance problems, and difficulty walking. Your mood and memory can also deteriorate. These symptoms sometimes develop slowly over months or years, which makes them easy to miss until the damage is significant.
Beyond B12, pay attention to iron, zinc, omega-3 fatty acids, calcium, and vitamin D. None of these are impossible to get from plants, but they require intentional food choices. Dark leafy greens, fortified plant milks, chia and flax seeds, lentils, and tofu can cover most gaps. Many vegans also benefit from an algae-based omega-3 supplement, since the form of omega-3 in flax and walnuts converts poorly to the type your brain and heart need most.
Protein is rarely the problem people think it is. Beans, lentils, tofu, tempeh, seitan, and whole grains provide plenty of protein for most adults. Athletes and older adults may need to be more deliberate about combining sources and hitting higher daily targets, but outright protein deficiency on a varied vegan diet is uncommon.
What It Actually Costs
A common assumption is that vegan eating is cheaper because you’re cutting out meat. The reality is more nuanced. Research from Dalhousie University found that plant-based specialty products (things like vegan cheese, plant-based burgers, and non-dairy yogurt) are on average 38% more expensive than their animal-based equivalents. If your vegan diet relies heavily on these processed alternatives, your grocery bill will likely go up.
A whole-foods approach tells a different story. Dried beans, lentils, rice, oats, frozen vegetables, tofu, and peanut butter are among the cheapest foods in any grocery store. If you build meals around these staples and treat specialty products as occasional additions rather than daily staples, a vegan diet can cost less than a typical omnivorous one. The price gap between the two approaches is really about how much convenience and familiar flavors you’re willing to pay for during the transition.
The Quality of Your Vegan Diet Matters
This point keeps surfacing across the research for a reason. A vegan diet built on whole grains, legumes, vegetables, fruits, nuts, and seeds delivers strong health and environmental benefits. A vegan diet built on refined carbohydrates, fried foods, and ultra-processed substitutes can increase your disease risk while still carrying a smaller environmental footprint than meat-heavy eating.
The people who thrive long-term on a vegan diet tend to share a few habits: they take B12 consistently, they eat a wide variety of whole plant foods, they don’t rely on processed vegan products as their primary nutrition, and they get periodic bloodwork to catch any deficiencies early. Going vegan is less of a single decision and more of a skill you develop over time, learning which combinations of foods keep you energized, satisfied, and well-nourished.