What Happens If You Cut Grains From Your Diet?

November 26, 2025 •

4 min read

According to a 2019 review, a long-term gluten-free diet can lead to micronutrient deficiencies in some individuals, including fiber, B vitamins, and minerals. This highlights the complex consequences of cutting grains from your diet and the importance of balanced nutritional planning.

Quick Summary

Eliminating grains affects blood sugar, digestion, and nutrient intake. Benefits can include weight management and less inflammation, while risks involve nutrient deficiencies and constipation if not properly managed with alternative foods like fruits and vegetables.

Key Points

Initial Adjustment Period: Expect a potential period of fatigue, headaches, or low energy as your body adapts to the removal of carbohydrates, sometimes called 'keto flu'.
Individual Digestive Response Varies: Cutting grains can reduce bloating and digestive upset for those with sensitivities, but a drop in fiber can cause constipation if not managed.
Mindful Nutrient Replacement is Crucial: Whole grains provide fiber, B vitamins, and minerals. Replace these with ample fruits, vegetables, nuts, seeds, and legumes to prevent deficiencies.
Not a Universal Prescription: While beneficial for specific conditions like celiac disease or some autoimmune disorders, a grain-free diet isn't medically necessary or healthier for everyone.
Focus on Whole Foods: The primary benefits of a grain-free diet often stem from the increased consumption of fruits, vegetables, and other whole foods, rather than just the absence of grains.
Sustainability and Restriction: A highly restrictive diet can be challenging to maintain long-term and may increase the risk of disordered eating patterns.

The Immediate Effects of Cutting Grains

When you first cut grains from your diet, your body undergoes several changes as it adjusts to the new eating pattern. The most immediate effects are often related to carbohydrate and fiber intake.

Energy and Blood Sugar Fluctuations

Grains are a major source of carbohydrates, which the body uses for energy. The sudden removal of this primary fuel source can lead to a period of adjustment. For those consuming refined grains that cause blood sugar spikes, removing them may lead to more stable blood sugar levels. However, some individuals may experience a temporary "keto flu" or withdrawal, with symptoms such as fatigue, headaches, and sluggishness, as their body switches to using fat for energy. Replacing refined grains with healthy fats and lean proteins can help mitigate these effects.

Digestive System Changes

Grains, especially whole grains, are a significant source of dietary fiber. A diet lacking this fiber can increase the risk of constipation as food moves more slowly through the digestive tract. Conversely, for those with sensitivities, like non-celiac gluten sensitivity or irritable bowel syndrome (IBS), removing grains can alleviate bloating, gas, and abdominal pain. In fact, one study showed a grain-free diet improved symptoms for 73% of participants with inflammatory bowel disease.

Long-Term Benefits and Potential Drawbacks

Sustaining a grain-free diet over the long term can have both positive and negative health outcomes, depending on how it is implemented. The key is to replace the nutrients lost from grains with other whole foods.

Table: Grain-Free Diet Pros and Cons


Potential Benefit	Potential Drawback
Reduced Inflammation: Especially for individuals with grain sensitivities or autoimmune conditions, removing potential inflammatory triggers like gluten can lower body-wide inflammation.	Nutrient Deficiencies: Eliminating fortified grains can lead to inadequate intake of B vitamins (thiamin, niacin, folate), iron, magnesium, and selenium.
Improved Blood Sugar Control: Without refined grains, blood sugar levels can be more stable, which is beneficial for managing and preventing diabetes.	Constipation Risk: Lower fiber intake from whole grains can increase the likelihood of constipation if not replaced with other fiber-rich foods.
Weight Management: Removing calorie-dense, often processed grains can reduce overall calorie intake and support weight loss.	Unsustainable and Restrictive: A highly restrictive diet can be difficult to maintain, potentially leading to disordered eating behaviors like orthorexia.
Enhanced Digestion (for some): For individuals with IBS or other sensitivities, removing grains can reduce digestive distress and symptoms.	Increased Saturated Fat Intake: Some might overcompensate for lost calories by increasing intake of high-fat foods, raising concerns about heart health.
Greater Nutrient Density from Alternatives: The need to replace grains can encourage higher consumption of nutrient-dense fruits, vegetables, nuts, and seeds.	Higher Risk of Heart Disease (for some): For those without sensitivities, avoiding whole grains removes protective nutrients, potentially increasing heart disease risk.

Nutrient Considerations and Replacements

Whole grains provide essential nutrients like fiber, B vitamins, and trace minerals that are less bioavailable or absent in refined alternatives. A well-planned grain-free diet must consciously replace these nutrients. For example:

Fiber: Increase intake of non-starchy vegetables, fruits, legumes, nuts, and seeds to ensure adequate fiber intake.
B Vitamins: Include leafy greens, legumes, and fortified nutritional yeast. Pseudocereals like quinoa and amaranth also offer some B vitamins.
Iron: Source iron from leafy greens, legumes, meat, and fortified foods. Pairing iron-rich foods with vitamin C-rich foods (like bell peppers or citrus) enhances absorption.
Magnesium and Selenium: Nuts, seeds, and leafy greens are excellent sources of these minerals.

Navigating a Grain-Free Diet Safely

For those who choose to cut grains, either for medical reasons or personal preference, a careful approach is essential to avoid negative side effects. The following steps can help ensure a balanced and healthy transition:

Prioritize Whole Foods: Focus on eating a wide variety of fruits, vegetables, lean proteins, healthy fats, nuts, seeds, and legumes. This ensures a diverse nutrient profile and helps replace the bulk that grains previously provided.
Explore Pseudocereals: These grain-like seeds, including quinoa, amaranth, and buckwheat, are often permitted on grain-free diets and offer a nutritional bridge between traditional grains and grain-free eating.
Read Labels Carefully: Grains and grain-derived ingredients are hidden in many processed foods, from sauces to snacks. Pay close attention to ingredients lists to avoid accidental consumption.
Meal Plan Strategically: Planning meals in advance helps prevent impulsive, less-healthy choices and ensures you are meeting your nutritional needs with a variety of foods.
Consult a Professional: Before making a major dietary change, especially if you have a health condition, it is wise to consult a doctor or a registered dietitian. This is particularly important for pregnant women, children, and those with a history of nutritional deficiencies or eating disorders.

Conclusion: Is a Grain-Free Diet Right for You?

Removing grains from your diet can produce significant health changes, both beneficial and challenging. While some individuals with specific sensitivities or autoimmune conditions may experience symptom relief, it is not a universally necessary or superior diet for everyone. The positive effects often come from the concurrent elimination of processed foods and increased consumption of nutrient-rich fruits and vegetables, benefits that can be achieved with a less restrictive diet as well. Potential risks, particularly nutrient deficiencies and constipation, can be mitigated with careful planning and diverse food choices. The decision to cut grains should be a well-considered one, ideally made in consultation with a healthcare professional, to ensure all nutritional needs are met sustainably. A balanced, whole-food-focused diet, whether grain-inclusive or grain-free, is the ultimate goal for long-term wellness. A comprehensive resource like Healthline provides further insights into the pros and cons of this diet: [https://www.healthline.com/nutrition/grain-free-diet].

Frequently Asked Questions

A grain-free diet eliminates all grains, including those that are naturally gluten-free like rice and corn. A gluten-free diet, in contrast, only removes grains containing the protein gluten, such as wheat, barley, and rye, but allows other grains.

It is often recommended to consider supplements, especially for B vitamins, iron, and magnesium, as these are often fortified in refined grains or naturally present in whole grains. Consulting a healthcare provider is essential to determine your specific needs.

Weight loss on a grain-free diet is often due to the reduction in overall calorie intake, especially from processed, high-calorie grain products like cookies and cakes. True weight loss is caused by a sustained calorie deficit.

Not all grains cause inflammation. While some research links refined grains to inflammation, whole grains often contain anti-inflammatory properties. A grain-free approach is primarily beneficial for those with confirmed sensitivities.

Some anecdotal and preliminary studies suggest a link between a grain-free diet and improved mood or reduced anxiety. However, the evidence is not conclusive, and more research is needed.

Excellent grain-free substitutes include starchy vegetables like sweet potatoes and squash, legumes, nuts, seeds, and fruits. Pseudocereals such as quinoa and buckwheat are also common alternatives.

You may notice immediate digestive changes like reduced bloating, but also potential fatigue and headaches in the first few days as your body adjusts its energy source.