What Happens When You Stop Eating All Grains?

November 1, 2025 •

4 min read

According to a 2018 study in Gastroenterology & Hepatology, individuals with certain digestive issues may benefit from a grain-free diet. This dietary shift, however, can cause significant physiological changes, raising the question: what happens when you stop eating all grains, and is it a sustainable choice for everyone?

Quick Summary

Eliminating all grains leads to significant physiological changes, including potential improvements in digestion and inflammation for some individuals, while posing risks of nutrient deficiencies and low energy for others. Outcomes are highly dependent on underlying health conditions and dietary replacements.

Key Points

Initial Withdrawal Symptoms: Expect fatigue, cravings, and potential moodiness, often called the 'carb flu,' as your body adjusts to a new energy source.
Nutrient Deficiency Risk: Removing grains can lead to deficiencies in fiber, B vitamins (like folate), and minerals (iron, magnesium) if not properly replaced with other food sources.
Potential Digestive Improvements: For those with sensitivities like celiac disease or IBS, eliminating grains can reduce bloating, discomfort, and improve overall digestive health.
Blood Sugar Regulation: Cutting carbohydrate-heavy grains can lead to more stable blood sugar levels, which is beneficial for managing metabolic conditions.
Weight Management Effects: Eliminating many processed grain-based foods can naturally reduce calorie intake, potentially leading to weight loss, but weight gain can occur if replaced with high-calorie alternatives.
Not for Everyone: Total grain elimination is unnecessary for most people without specific medical conditions and can be overly restrictive and difficult to sustain long-term.
Impact on Gut Health: The reduction of fiber from whole grains can negatively affect the gut microbiome and potentially lead to constipation.

The Immediate Effects of Eliminating Grains

When you first stop eating all grains, your body undergoes several rapid adjustments. For many, particularly those sensitive to gluten or other grain components, initial symptoms may include improvements in digestion, less bloating, and a reduction in discomfort. However, cutting out a major source of carbohydrates can also lead to a drop in blood sugar and energy levels, causing a period of fatigue, cravings, and potential moodiness. This phase is often described as the 'carb flu,' where the body adapts to burning fats for energy instead of glucose from carbohydrates.

Potential Benefits and Positive Changes

For certain individuals, a grain-free diet can unlock several health improvements:

Reduced Inflammation: Grains, particularly refined varieties, can contribute to chronic inflammation in some people. Removing them may alleviate inflammation-related issues, such as autoimmune disorder symptoms.
Improved Blood Sugar Control: By eliminating grains, which are high in carbohydrates, blood sugar spikes can become more stable, which is beneficial for managing diabetes or metabolic syndrome.
Weight Loss: Many processed, high-calorie, and low-nutrient foods like cookies and white bread are eliminated, which naturally reduces overall calorie intake and can lead to weight loss.
Better Digestive Health: For those with celiac disease, gluten sensitivity, or Irritable Bowel Syndrome (IBS), removing grains can drastically improve symptoms like bloating, abdominal pain, and diarrhea.

Risks and Potential Nutrient Deficiencies

Despite the possible benefits, a grain-free diet carries notable risks, particularly regarding nutritional intake. Whole grains are a significant source of many essential vitamins, minerals, and fiber. Simply removing them without proper replacement can lead to serious deficiencies.

Common Nutrient Deficiencies on a Grain-Free Diet

Whole grains are fortified with many crucial nutrients. Eliminating them without compensating for these losses can lead to deficiencies in:

Dietary Fiber: Found abundantly in whole grains, fiber is vital for digestive regularity and overall gut health. Its loss can lead to constipation.
B Vitamins: Grains are a major source of B vitamins like thiamin, niacin, and folate, which are important for energy metabolism and cell function. Folate is especially critical for women of childbearing age to prevent birth defects.
Minerals: Important minerals like iron, magnesium, manganese, and selenium are often found in whole grains. Deficiencies can lead to issues like anemia, muscle cramps, and metabolic problems.

How to Manage a Grain-Free Diet Safely

If you have a medical reason to stop eating all grains, working with a healthcare professional or registered dietitian is crucial to ensure nutritional balance. Replacements must be carefully chosen to avoid deficiencies and maintain energy levels. A comprehensive grain-free diet should prioritize a wide variety of nutrient-dense whole foods.

Comparison of Grain-Free vs. Whole-Grain Diets


Feature	Grain-Free Diet	Whole-Grain Inclusive Diet
Primary Energy Source	Relies on fats, proteins, fruits, and vegetables for energy.	Uses carbohydrates from grains as a primary energy source.
Key Nutrient Sources	Nuts, seeds, legumes, fruits, vegetables, meat, and dairy.	Grains (wheat, rice, oats), legumes, fruits, and vegetables.
Digestive Impact	Can relieve symptoms for those with sensitivities, but fiber must be replaced.	Promotes regularity and gut health due to high fiber content.
Inflammation	May reduce chronic inflammation for some sensitive individuals.	Whole grains have anti-inflammatory benefits, though processed grains can increase it.
Nutrient Deficiency Risk	High risk of deficiencies (B vitamins, iron, magnesium) without careful planning.	Lower risk of deficiencies, as many grains are fortified.

The Challenge of a Grain-Free Lifestyle

A grain-free diet is extremely restrictive and requires constant vigilance. Grains are hidden in many processed foods, from soups and sauces to seasonings. This can make dining out or purchasing pre-packaged meals difficult. For those without specific health conditions like celiac disease, the total elimination of grains may be an unnecessarily restrictive approach that isn't sustainable long-term. Focus should be placed on whole, nutrient-dense foods rather than simply avoiding an entire food group without cause.

Conclusion

For some individuals with specific health conditions like celiac disease or severe gluten sensitivity, stopping all grains can significantly improve their quality of life. The benefits can include reduced inflammation, better digestion, and improved blood sugar control. However, for most people, an all-or-nothing approach to grains is not necessary and can lead to significant nutritional deficiencies, such as a lack of fiber, B vitamins, and essential minerals. The most sustainable and healthy approach for the general population is moderation, focusing on nutrient-rich whole grains while limiting refined and processed grain products. Consulting a medical professional or registered dietitian before making drastic dietary changes is always recommended.

The Gut Microbiome and Grains

Emerging research suggests that whole grains play a role in fostering a healthy gut microbiome. Fiber, in particular, feeds the beneficial bacteria in your gut. Drastically cutting this fiber source could alter your gut flora, potentially impacting not only digestion but also overall immunity and even brain function. Conversely, some studies suggest that for people with certain inflammatory issues, removing specific grains can help restore gut balance. The impact is highly individualized and complex.

Here is a helpful resource on the importance of whole grains

What are pseudocereals?

Some diets allow for pseudocereals like quinoa, buckwheat, and amaranth, which are botanically seeds but used like grains. These can be an excellent way to replace some of the nutrients and fiber lost from eliminating true grains, but they require careful planning and may not fully compensate for the complete nutritional profile of whole grains.

Frequently Asked Questions

Weight loss can occur initially because eliminating grains often means cutting out many calorie-dense, processed foods. However, this is largely due to a reduction in total calories, and sustainable weight loss depends on replacing grains with other whole, nutritious foods and maintaining a calorie deficit.

Yes, a grain-free diet can cause constipation because whole grains are a major source of dietary fiber. Without replacing this fiber with other high-fiber sources like fruits, vegetables, nuts, and legumes, you may experience digestive issues.

For most people without a medical need, stopping all grains is not necessary and can be detrimental. It increases the risk of nutrient deficiencies in fiber, B vitamins, and minerals. It is best to consult a dietitian or doctor.

Your energy levels may initially drop as your body adjusts from burning carbohydrates for fuel to using fat. This period, known as the 'carb flu,' typically passes as your body becomes more efficient at using other energy sources.

You can replace grains with nutrient-dense foods such as fruits, vegetables, legumes, nuts, seeds, lean meats, fish, and dairy products (if tolerated). Pseudocereals like quinoa and buckwheat are also excellent substitutes.

For individuals with gluten sensitivity, celiac disease, or other digestive issues, eliminating grains can lead to a significant reduction in bloating and stomach discomfort.

Whole grains are a valuable source of essential nutrients, including dietary fiber, B vitamins (thiamin, niacin, folate), and minerals such as iron, magnesium, manganese, and selenium.