This eating plan is considered a fad diet. Fad diets often promote quick weight loss that is unsustainable and may severely restrict what you eat. They may be harmful and generally do not have long-lasting health benefits. Talk to your healthcare provider before making any major changes to how you eat.
The All-Bran diet is a short-term eating plan. It was originally promoted by Kellogg’s to help improve digestion, relieve bloating, and support bowel regularity by increasing fiber intake through daily servings of its All-Bran cereal.
While no longer widely marketed in the United States, the diet encourages replacing lower-fiber foods with high-fiber alternatives to boost daily fiber consumption to promote digestive health. Proponents claim it eases bloating and sluggishness while improving overall health.
How Does the All-Bran Diet Claim to Work?
According to a 2004 press release from the Kellogg’s company, the All-Bran diet is a high-fiber eating plan designed to improve digestion and promote regular bowel movements.
It centers on the idea that increasing your daily fiber intake — especially insoluble fiber found in wheat bran — can help relieve constipation, reduce bloating, and support overall gut health.
While the branded version of the diet suggests eating at least a 1/2 cup of All-Bran cereal daily for 5 to 14 days, some versions encourage replacing low-fiber meals and snacks with higher-fiber options to help “reset” the digestive system.
Supporters also claim the diet may aid in weight management. That’s because fiber-rich foods are typically more filling. This may help curb appetite and reduce overall calorie intake without the need for strict portion control or eliminating food groups.
However, any weight loss is likely to be modest and temporary, especially if the diet is only followed for a few days or weeks.
What Can You Eat on the All-Bran Diet?
The All-Bran diet emphasizes eating fiber-rich foods, especially wheat bran cereal, to support digestive health.
Foods to Include
Aim for a 1/2 cup of Kellogg’s All-Bran cereal per day and high-fiber vegetables, fruits, and legumes.
Foods to Avoid
No foods are restricted on the All-Bran diet. Instead, you’re encouraged to replace a low-fiber or processed meal with a serving of Kellogg’s All-Bran cereal.
Potential Benefits of the All-Bran Diet (and Why They May Not Last)
While there’s no published research on the All-Bran diet itself, the plan is essentially a high-fiber eating approach. There’s strong evidence linking increased fiber intake to a range of health benefits, according to research:
- Improved Digestion and Regularity Fiber — especially insoluble fiber like wheat bran — can help soften stool, reduce constipation, and support overall gut health.
- Appetite Control and Modest Weight Loss High-fiber foods tend to be more filling, which may help reduce overall calorie intake without strict calorie counting.
- Heart Health and Cholesterol Support Soluble fiber may help lower LDL (“bad”) cholesterol and support healthy blood pressure.
- Blood Sugar Stability According to the Centers for Disease Control and Prevention (CDC), fiber slows digestion, helping prevent blood sugar spikes after meals.
- Better Long-Term Health Diets rich in fiber are associated with a lower risk of cardiovascular diseases, according to research. One study found an association between a fiber-rich diet and a lower risk of dying from cancer.
That said, many of these effects may be short-lived if the diet is only followed for a few days or weeks. Lasting benefits require consistent, long-term fiber intake from a variety of plant-based sources — not just cereal alone.
Potential Risks of the All-Bran Diet
While a high-fiber diet offers clear health benefits, ramping up fiber too quickly, especially from a single source like bran cereal, can cause unwanted side effects, such as:
- Digestive Discomfort Bloating, gas, and cramping can occur if your body isn’t used to high fiber, particularly when intake increases suddenly or without enough water, according to Mayo Clinic.
- Nutrient Gaps Relying too heavily on one food, like All-Bran cereal, can crowd out other nutrient-dense options and lead to an unbalanced diet.
- Problems for People With GI Conditions People with certain gastrointestinal (GI) conditions, such as irritable bowel syndrome (IBS), Crohn’s disease, or a history of bowel obstruction, may need to limit or avoid high-fiber foods like bran, according to Cleveland Clinic.
As with any dietary shift, it’s best to make changes gradually and talk to your healthcare provider, especially if you have a medical condition or take daily medications.
Is the All-Bran Diet Right for You?
Although the All-Bran diet is marketed as a simple way to improve digestion, it still falls under the category of a fad diet: one that encourages quick fixes rather than long-term habits.
While increasing fiber can support digestive and overall health, relying on a single food for results is rarely sustainable or balanced.
Like many short-term eating plans, the All-Bran diet may lead to temporary changes, but it doesn’t offer the variety or flexibility needed for lasting health benefits.
If you're interested in boosting your fiber intake, a more individualized, long-term approach — built on a variety of plant-based foods — is likely to be more effective.
Talk to your healthcare provider or a registered dietitian before starting any new diet, especially if you have underlying health conditions or take medications.
