Is there any benefit to eating grass?

November 12, 2025 •

4 min read

According to a study published in the Proceedings of the National Academy of Sciences, ancient human ancestors consumed significant amounts of grasses and sedges around 3.5 million years ago. However, the question remains: is there any benefit to eating grass today for modern humans? The answer is a complex one that distinguishes between fibrous lawn grass and nutritionally potent cereal grasses.

Quick Summary

This article explores the negligible nutritional value and significant health risks of eating common grass, contrasting it with the benefits of concentrated cereal grasses like wheatgrass. It details why the human digestive system is not equipped to process the cellulose found in fibrous grass blades. It also outlines the potential dangers, from tooth damage to digestive distress, associated with raw grass consumption.

Key Points

Not all grass is created equal: Common lawn grass is largely indigestible and harmful for humans to eat, while certain cereal grasses like wheatgrass offer nutritional benefits when processed.
Humans lack the right digestive tools: Our single-chambered stomach and absence of the enzyme cellulase prevent us from breaking down the fibrous cellulose in grass for energy, unlike ruminants.
Eating lawn grass carries risks: Consuming unprocessed grass can cause digestive problems like bloating and diarrhea, damage tooth enamel due to abrasive silica, and expose you to dangerous pesticides and parasites.
Cereal grasses are nutrient powerhouses: Young cereal grasses harvested for juicing or supplements are rich in vitamins (A, C, E), minerals (calcium, iron), and antioxidants.
Preparation is key for safety and absorption: The nutritional benefits of 'eating grass' come from consuming processed forms like juice or powder, not chewing on raw blades.
Consider safety first: To gain any benefit, choose commercially prepared supplements from reputable sources, avoiding the many hazards associated with eating unknown or wild grass.

Why the Human Digestive System Can't Handle Common Grass

Despite the apparent abundance of grass in our environment, the human body is simply not built to digest it effectively. The primary reason for this lies in our inability to break down cellulose and lignin, the tough organic polymers that form the structural walls of plant cells. Herbivores, such as cows and sheep, are equipped with multi-chambered stomachs and specialized symbiotic bacteria that produce the enzyme cellulase to break down this material. Humans lack this crucial enzyme and the digestive apparatus required for rumination (repeated chewing and re-swallowing).

Indigestible cellulose and minimal nutrient absorption

When a human consumes typical lawn grass, the cellulose passes through the digestive tract largely intact, functioning as a form of insoluble fiber. While insoluble fiber is beneficial for digestive health, it offers no caloric or nutrient value from the grass itself. The limited nutrients contained within the grass's cell walls remain locked away, rendering the plant essentially indigestible as a food source. This is why relying on grass for sustenance would lead to rapid malnutrition and starvation, as the body cannot extract the necessary energy.

Serious health risks and potential dangers

Beyond the lack of nutrition, attempting to subsist on a grass-based diet comes with considerable health risks:

Tooth damage: Grass contains a high amount of silica, a hard, abrasive compound that can wear down tooth enamel over time. Unlike grazing animals with continuously growing teeth, human dental structure is not built to withstand this abrasive material.
Digestive distress: Consuming large quantities of fibrous, indigestible grass can cause significant gastrointestinal upset, including bloating, gas, stomach pain, and diarrhea. In extreme cases, a buildup of fibrous material can cause a bezoar, a solid mass that can obstruct the digestive tract.
Exposure to toxins: Foraged grass, especially from urban or suburban areas, is often treated with pesticides, herbicides, and other harmful chemicals. It can also harbor parasites, bacteria, and waste products from animals, posing a significant risk of illness.

The notable exception: Cereal grasses like wheatgrass

While eating common lawn grass is ill-advised, humans do consume and benefit from certain types of cereal grasses, such as wheatgrass and barley grass. These are harvested at a young, vegetative stage before developing high levels of indigestible cellulose. At this stage, they are packed with nutrients and are typically consumed as juice or a powdered supplement, not chewed whole.

Wheatgrass and barley grass benefits

Rich in vitamins and minerals: Cereal grasses are a concentrated source of vitamins A, C, E, K, and B-complex vitamins, along with minerals like magnesium, calcium, iron, and potassium.
Antioxidant properties: They contain a high level of antioxidants, which help combat free radicals in the body and reduce oxidative stress.
High chlorophyll content: Wheatgrass is particularly rich in chlorophyll, which is believed to aid in detoxification, improve blood circulation, and boost energy levels.
Dietary support: In supplemental form, these grasses can help support the immune system, lower cholesterol, and aid in digestion.

Comparison: Common Lawn Grass vs. Cereal Grass


Feature	Common Lawn Grass	Cereal Grass (e.g., Wheatgrass)
Primary Composition	High in indigestible cellulose and lignin; mostly water.	High in vitamins, minerals, antioxidants, and chlorophyll.
Digestibility for Humans	Extremely poor. The human gut cannot break it down and extract nutrients.	Highly digestible when consumed as a juice or processed powder.
Nutritional Value	Negligible. Provides almost no calories or absorbable nutrients.	Nutrient-dense, providing concentrated vitamins, minerals, and amino acids.
Health Risks	Potential for dental damage (silica), digestive issues (bloating, diarrhea), and exposure to toxins (pesticides, parasites).	Generally safe for consumption as a supplement, though individual tolerance varies.
Form of Consumption	Attempting to eat raw, chewed blades is dangerous and impractical.	Processed into juices, powders, or supplements for easy absorption.

Conclusion: The correct way to consume 'grass'

The question of whether there is a benefit to eating grass depends entirely on the type of grass and its preparation. Consuming fibrous, unprocessed lawn grass is not only nutritionally useless for humans but is also harmful due to our digestive limitations and the presence of abrasive silica and potential toxins. The benefit lies in the consumption of specialized cereal grasses like wheatgrass, which are harvested young and processed to deliver a concentrated dose of nutrients. So, while you should leave the lawn alone, incorporating a quality wheatgrass supplement or juice might provide a genuine health boost. Always opt for safe, cultivated products over a mouthful of garden variety grass. For those interested in exploring plant-based protein alternatives, research into processed grass protein concentrates for human consumption is ongoing and may represent a sustainable food source in the future.

Frequently Asked Questions

Humans cannot digest regular lawn grass because we lack the necessary enzymes, specifically cellulase, to break down the tough cellulose and lignin in plant cell walls. Our digestive systems are not adapted for processing such fibrous material efficiently.

Yes, eating common lawn grass can be dangerous. It provides no nutritional value and can cause digestive issues like bloating and diarrhea. It also contains abrasive silica that can harm your teeth and may be contaminated with harmful pesticides or parasites.

Wheatgrass is a specific type of cereal grass harvested at a young stage when its nutrient content is high and cellulose is minimal. It is typically consumed as a juice or supplement. Regular lawn grass is full of indigestible cellulose and offers no nutritional benefit.

No, in a survival situation, eating grass is a poor strategy. While it might temporarily fill your stomach, your body cannot extract any meaningful nutrition from it. You would still starve, and could suffer from severe digestive distress.

Wheatgrass juice is known for its high concentration of vitamins (A, C, E, K), minerals, and chlorophyll. It acts as an antioxidant, boosts the immune system, and can aid in detoxification. It's consumed for overall health and vitality.

Studies of ancient human ancestors show that some species, like Australopithecus, incorporated grasses and sedges into their diet millions of years ago. However, they likely consumed roots, corms, or tubers rather than the tough blades, and modern human digestive systems have evolved differently.

To get the benefits of cereal grasses, use commercially prepared wheatgrass or barley grass supplements. These are processed to be digestible and are rich in nutrients, providing a safe alternative to eating unprocessed grass.