The low fiber, fat limited exclusion (LOFFLEX) diet is a type of elimination diet prescribed for Crohn’s disease.

The diet was developed in 1998 after the observation that people with Crohn’s disease commonly reported symptoms after eating foods high in fiber and fat.

However, you may wonder what the diet consists of and whether it’s effective for managing symptoms.

This article explains what to eat and avoid on the LOFFLEX diet and provides a 3-day sample LOFFLEX diet menu.

LOFFLEX diet

What is the LOFFLEX diet?

The LOFFLEX diet is a type of elimination diet that restricts fiber and fat.

It was first described in 1998 as a way to prolong symptom relief after it’s achieved with exclusive enteral nutrition (EEN) — an all-liquid diet that provides nutrition orally or by a feeding tube — in patients with Crohn’s disease (1).

Crohn’s disease is a type of inflammatory bowel disease (IBD) that affects any part of the digestive tract.

Ulcerative colitis is the other primary form of IBD that affects only the colon or large intestine.

It’s common for people with Crohn’s disease to experience periods of remission with minimal symptoms, and active phases when symptoms flare.

During active periods when the digestive tract becomes inflamed, common symptoms experienced are abdominal pain, bloating, diarrhea, fever, and fatigue.

The LOFFLEX diet was developed based on evidence that a small number of people with Crohn’s disease commonly reported symptoms after reintroducing high-fiber and high-fat foods to their diets following EEN or an elemental diet (1).

Indeed, high-fat diets have been associated with lower remission rates, with more conflicting results on the link between fiber and symptom development (1).

But because transitioning from a low-fiber enteral diet to a whole foods diet can cause digestive discomfort, the LOFFLEX limits fibers initially and then builds up gradually to a tolerable amount.

The LOFFLEX diet limits fat to 50 grams per day and fiber to 10 grams daily.

Getting started on the LOFFLEX diet

It’s recommended to follow the LOFFLEX diet for two weeks but it may be necessary to follow it for up to four weeks if symptoms don’t improve (1).

Here are the foods to avoid and eat on the LOFFLEX diet (1):

Foods to avoid:

  • Fruits: apples, bananas, dried fruit, and citrus fruits, including oranges, tangerines, clementines, mandarins, grapefruits, lemons, and limes
  • Vegetables and legumes: peas, beans, lentils, onions, parsnips, sweetcorn, and tomatoes
  • Grains: wheat, rye, barley, corn, and oats
  • Meats and poultry: pork and processed meat products, including sausages, deli meats, bologna, beef jerky, and hot dogs
  • Seeds and nuts
  • Seafood: fish that is fried or canned in oil
  • Dairy alternatives: soy milk and products
  • Oils: corn and nut oils
  • Condiments: gravy mixes and salad dressings
  • Beverages: caffeinated tea and coffee, alcohol, and soda

Avoid using high-fat cooking methods such as deep-fat frying, roasting, and frying with large amounts of oil.

Foods to eat:

  • Fruits: all other fresh, tinned, or cooked fruits; remove skins, seeds, and pits
  • Vegetables: all other vegetables; remove skins, seeds, and stalks
  • Grains: rice, rice cakes, tapioca, sago, and arrowroot
  • Dairy alternatives: soy milk or other plant-based dairy alternatives
  • Meat and poultry: all lean meat and skinless poultry
  • Seafood: all types of fresh or frozen fish and shellfish and fish canned in water
  • Oils: sunflower and olive oil
  • Condiments: salt, pepper, herbs, spices, sugar, honey, and jam
  • Beverages: decaffeinated tea and coffee, herbal teas, water, non-citrus fruit juice

Stick with low-fat cooking methods, such as baking, steaming, grilling, dry-roasting, and frying with low-calorie spray oils.

Reintroduction stage

After following the LOFFLEX diet for at least two weeks, it’s time to reintroduce the foods that you initially restricted.

Begin by reintroducing foods, one at a time, for at least four days while you monitor for symptoms before reintroducing the next.

With wheat or wheat products, you should allow at least seven days before reintroducing the next food since the onset of symptoms tends to be delayed.

If your symptoms don’t return when testing a food, you can assume that food is “safe” and include it in your diet going forward.

If your symptoms do return when testing a food, that item was likely responsible and should be excluded from your diet.

It’s best to keep a food diary so you can accurately track which foods you have reintroduced and whether they provoked any symptoms.

You should also document the amount of each food you consume as there may be a limit on how much of a food you can eat before it triggers your symptoms.

At the end of this stage, you will have identified your “safe” diet, which will include foods that you can eat without triggering symptoms.

3-day sample LOFFLEX diet menu

Here’s a 3-day sample LOFFLEX diet menu:

Day 1

  • Breakfast: puffed rice cereal with fortified soy milk
  • Lunch: grilled chicken salad
  • Snack: soy milkshake
  • Dinner: salmon, white rice, and green beans

Day 2

  • Breakfast: rice cakes with margarine and jam
  • Lunch: fish cakes coated with rice flour
  • Snack: soy yogurt with peaches
  • Dinner: roasted chicken with potatoes and broccoli florets (stocks trimmed)

Day 3

  • Breakfast: potato cakes and pear slices
  • Lunch: carrot and coriander soup
  • Snack: soy milkshake
  • Dinner: sirloin steak, mashed potato with margarine, and asparagus tips

Benefits

To date, only one small study has examined the effects of the LOFFLEX diet on managing Crohn’s disease symptoms.

The trial was conducted in 1998 and demonstrated that nearly 56% of patients with Crohn’s disease who followed the LOFFLEX diet were likely to remain in remission after two years (1).

The authors concluded that the LOFFLEX diet may be a good alternative to steroids, which are commonly prescribed to lower inflammation and reduce symptoms.

However, the study was not a randomized controlled trial, limiting the strength of the findings.

Still, the LOFFLEX diet continues to be recommended for Crohn’s disease, albeit less often than other diets, such as the low-FODMAP diet, specific carbohydrate diet, and autoimmune protocol diet (AIP).

Downsides

Despite the potential benefits of the LOFFLEX diet for managing Crohn’s disease, it has several downsides to consider.

Keep in mind that the LOFFLEX diet is designed to help reintroduce foods after achieving remission with EEN.

As such, it’s unknown whether following the LOFFLEX diet would be effective for inducing remission during a flare-up when symptoms are active.

The diet is also difficult to follow correctly without the guidance of a registered dietitian.

This is why most studies evaluating the effectiveness of elimination diets have prescribed them under the guidance of a registered dietitian to ensure that patients correctly identify trigger foods and that their diet is nutritionally adequate.

Therefore, if you intend to try the LOFFLEX diet, you should do so with the help of a dietitian to avoid unnecessary food restrictions and to make sure you’re getting enough nutrients.

Still, because Crohn’s disease is highly individual and foods that provoke or worsen symptoms in one person may not in the next, the LOFFLEX diet likely won’t work for everyone (2, 3, 4).

The bottom line

The LOFFLEX diet limits foods that are high in fiber and fat, which are thought to trigger or worsen symptoms in people with Crohn’s disease.

It’s prescribed following EEN as a way to reintroduce foods without triggering symptoms.

Unfortunately, there is limited evidence to support its use for achieving or maintaining remission with Crohn’s disease.

However, if you wish to try the LOFFLEX diet, it’s best to do so under the guidance of a registered dietitian.


Gavin Van De Walle, MS, RD, LN
Gavin Van De Walle, MS, RD, LN

Gavin Van De Walle holds a master's degree in human nutrition and bioenergetics. He is a registered dietitian who aims to arm the public with evidence-based nutrition recommendations so they can make their own educated and informed health decisions.