What Can I Eat to Gain Weight with IBS?

November 17, 2025 •

4 min read

According to the National Institutes of Health, many people with IBS struggle with managing their weight due to dietary restrictions and symptom-induced appetite changes. This guide reveals exactly what can I eat to gain weight with IBS, focusing on nutrient-dense, low-FODMAP options to boost your calorie intake without triggering a flare-up.

Quick Summary

This article provides a comprehensive guide to gaining weight while managing Irritable Bowel Syndrome. It outlines suitable high-calorie, low-FODMAP foods, from healthy fats and proteins to starchy carbohydrates, and offers strategic eating tips to maximize calorie intake. The content includes guidance on meal planning, supplements, and lifestyle adjustments to support healthy weight gain while minimizing digestive discomfort.

Key Points

Embrace High-Calorie, Low-FODMAP Foods: Prioritize nutrient-dense foods like healthy fats and proteins that are less likely to trigger IBS symptoms, such as olive oil, nuts, lean meats, and lactose-free dairy.
Adopt Frequent, Small Meals: Rather than large meals that can overwhelm the digestive system, eat smaller, more frequent meals every 2-3 hours to maintain a steady calorie intake and minimize digestive discomfort.
Fortify Your Food for Extra Calories: Add calorie-dense ingredients to your existing meals without adding bulk. Examples include swirling olive oil into potatoes, adding nuts to salads, or using nut butters in smoothies.
Drink Nutrient-Dense Smoothies: Boost your liquid calories with homemade low-FODMAP smoothies using lactose-free milk, unripe banana, nut butter, and a suitable protein powder like whey isolate or pea protein.
Strategically Choose Carbohydrates: Focus on easily digestible starchy carbs like white rice, oats, and potatoes, which provide energy without the high-FODMAP content found in wheat and other grains.
Track Your Triggers and Progress: Keep a food and symptom diary to identify which specific foods and eating patterns work best for your unique IBS, helping to refine your weight gain strategy over time.

Gaining Weight with IBS: The Core Principles

Navigating weight gain with a sensitive digestive system like IBS requires a strategic and gentle approach. The goal is to increase your calorie intake by focusing on nutrient-dense, high-energy foods that are less likely to cause digestive distress. This often means following a low-FODMAP protocol, which restricts certain carbohydrates that ferment in the gut and cause symptoms like bloating, gas, and discomfort. By choosing the right foods and adopting smart eating habits, you can support a healthy weight without aggravating your condition.

Prioritizing High-Calorie, Low-FODMAP Foods

The foundation of a successful weight gain plan for IBS is incorporating calorie-dense foods that fit within a low-FODMAP framework. Healthy fats and proteins are particularly valuable because they are naturally high in calories and typically low in FODMAPs.

Healthy Fats and Oils: Olive oil and avocado oil can be added to meals and salads to boost calories without increasing bulk. Nuts like peanuts, macadamias, and walnuts are excellent high-calorie snacks, as are seeds such as pumpkin and sunflower seeds. Avocado, in small portions, is also a great source of healthy fats.
Proteins: Lean meats such as chicken, turkey, beef, and fish are all excellent sources of low-FODMAP protein. Eggs are a versatile and nutrient-dense option, and firm tofu or tempeh can be included for plant-based protein. For dairy, consider lactose-free milk, yogurt, and hard cheeses.
Starchy Carbohydrates: Unlike high-FODMAP grains like wheat and rye, certain starchy carbs can be very helpful for weight gain. Rice, oats, quinoa, and potatoes are well-tolerated and provide energy. Consider a serving of gluten-free pasta or spelt sourdough bread in moderation.

Strategic Eating and Meal Planning

In addition to food choices, how and when you eat can significantly impact your weight gain and IBS symptoms. For those with a small appetite or easily triggered by large meals, frequent, smaller meals are often more effective than three large ones.

Eat Small, Frequent Meals: Aim for 5-6 smaller meals or snacks throughout the day, roughly every 2-3 hours. This prevents the digestive system from becoming overwhelmed and allows for consistent calorie intake.
Make Every Bite Count: Fortify your meals and snacks with calorie-dense additions. Stir olive oil into mashed potatoes, add nut butter to smoothies, or sprinkle nuts and seeds over lactose-free yogurt.
Boost Your Beverages: Drink your calories with nutrient-dense, low-FODMAP smoothies. Blend lactose-free milk or soy protein milk with a safe serving of fruit like bananas or blueberries, a spoonful of nut butter, and a scoop of a suitable protein powder.

Low-FODMAP Weight Gain Smoothies

Making your own smoothies is a simple way to increase calories and pack in nutrients without adding bulk. Here's a basic recipe to build from:

Base: 1 cup lactose-free whole milk or soy protein milk
Fruit: 1 ripe, medium banana or a handful of strawberries
Healthy Fats: 1-2 tablespoons of peanut or almond butter
Protein Boost: 1 scoop of a low-FODMAP protein powder like whey protein isolate or pea protein
Optional Extras: Add chia seeds, hemp seeds, or a small amount of low-FODMAP oats for extra calories and fiber.

Comparing High-Calorie Foods for IBS


Food Category	Low-FODMAP, High-Calorie Options	High-FODMAP, High-Calorie Options to Avoid
Healthy Fats	Peanut butter, almond butter, olive oil, walnuts, macadamia nuts	Cashews, pistachios, large portions of avocado
Proteins	Lean chicken, turkey, beef, fish, eggs, firm tofu	Sausages, processed meats with onion/garlic, large portions of canned lentils/beans
Carbohydrates	White rice, gluten-free pasta, potatoes, oats, quinoa, spelt sourdough bread	Wheat bread, rye, high-fructose corn syrup, honey, most commercial cereals
Dairy	Lactose-free whole milk, hard cheeses (cheddar, parmesan), lactose-free yogurt	Regular cow's milk, soft cheeses, ice cream
Fruits	Unripe bananas, cantaloupe, strawberries, oranges, blueberries	Apples, pears, mangoes, cherries, dried fruit

Conclusion

Successfully navigating weight gain with IBS is a journey of finding a balanced, individualized approach that prioritizes nutrient-dense, high-calorie foods while respecting digestive sensitivities. By focusing on low-FODMAP, high-energy options, incorporating healthy fats and proteins, and adopting strategic eating patterns like smaller, more frequent meals, it is possible to increase your body weight without triggering painful symptoms. Consistency is key, and personal tolerance should always be the guiding factor. Working with a dietitian can provide tailored guidance to ensure your plan is both effective and comfortable. A holistic approach that includes diet management, stress reduction, and mindful eating practices can help you achieve your weight goals and improve your overall digestive well-being.

Seeking Professional Guidance

While the information provided offers a strong starting point, it is always recommended to consult with a healthcare professional, such as a registered dietitian, before making significant dietary changes, especially when managing a chronic condition like IBS. A professional can help you create a personalized plan and guide you through the reintroduction phases of the low-FODMAP diet to identify your specific triggers. Find an IBS-specialist dietitian through a trusted resource like the American College of Gastroenterology.

Frequently Asked Questions

For those with IBS, the best protein powders are typically whey protein isolate or pea protein, as they are low in FODMAPs. Whey protein isolate has most of the lactose removed, making it easier to digest for many people, while pea protein is a plant-based alternative.

Yes, it is entirely possible to gain weight on a low-FODMAP diet. The key is to focus on calorie-dense, low-FODMAP foods such as healthy fats (oils, nuts, seeds), lean proteins, and easily digestible carbohydrates like rice and potatoes to increase your energy intake.

To increase calories without bulk, incorporate healthy fats and oils. Add a tablespoon of olive oil or butter to cooked foods, spread nut butter on low-FODMAP toast or fruit, and snack on high-calorie nuts like macadamias and walnuts.

For most people with IBS, eating smaller, more frequent meals (5-6 times per day) is more beneficial than large meals. This approach reduces stress on the digestive system and ensures a more consistent calorie intake throughout the day.

Low-FODMAP fruits suitable for weight gain include unripe bananas, cantaloupe, strawberries, blueberries, and oranges. Ripe bananas can also be tolerated in specific portion sizes.

If you are lactose intolerant or sensitive to dairy, use lactose-free dairy products like full-fat lactose-free milk and yogurt. Hard cheeses, such as cheddar and parmesan, are also naturally low in lactose and often well-tolerated.

No, many nuts and seeds are low-FODMAP and excellent for weight gain. Peanuts, macadamias, walnuts, and pumpkin seeds are good options. However, nuts like cashews and pistachios are high in FODMAPs and should be avoided or consumed in very small, tested portions.

Yes, stress can significantly impact IBS symptoms and appetite. Managing stress through techniques like mindfulness, yoga, and meditation can help regulate appetite and improve digestive function, supporting healthy weight gain.