The F-Factor Diet was created by Tanya Zuckerbrot, a registered dietitian. It comes with a food line, meal plan, and other branded products. The F-Factor Diet book was released in 2006.

The “F” in F-Factor stands for fiber, a nutrient that most people don’t get enough of. Fiber is an indigestible carb that adds bulk to foods (1, 2).

The F-Factor plan is based on foods that are high in fiber, lean protein, and complex carbs.

Its four core principles make it different from many other diet plans:

• eating the right kinds of carbs
• eating out at restaurants
• drinking alcohol if you choose to
• spending less time exercising

The F-Factor Diet emphasizes flexibility and doesn’t require you to restrict yourself when it comes to eating out or enjoying alcohol in moderation.

The diet is designed to be more sustainable than many other dietary approaches. The creator says that it’s based on the science of anatomy and physiology, which don’t change with dieting.

SUMMARY

The F-Factor Diet is designed for weight loss and based on eating high fiber foods and lean proteins. It encourages flexibility and doesn’t restrict food or alcohol or require you to exercise.

The F-Factor Diet aims for three meals plus one snack per day. It combines lean proteins with high fiber foods and is designed to be low in calories, keep you full longer, and prevent feelings of deprivation.

There are several phases to the F-Factor Diet. Each increases your net carb intake until you reach your carb goal. Net carbs are the digestible carbs your body breaks down and absorbs, after accounting for any sugar alcohols and fiber.

They’re generally calculated by subtracting the fiber content from the grams of carbs in a serving of food.

Note that the F-Factor Diet would be considered a low-carb diet, which consists of 20–130 grams of carbs per day (3).

The diet emphasizes complex carbs like fruits, vegetables, whole grains, nuts, and seeds over simple carbs like refined grains, added sugar, and highly processed foods.

In phase 1, the F-Factor Diet incorporates fewer than 35 grams of net carbs per day. This is spread over approximately 3 servings of carbs. This is meant to jump-start your weight loss.

In phase 2, you incorporate fewer than 75 grams of net carbs per day. This is spread over approximately 6 servings of carbs.

The last phase of the F-Factor Diet is the maintenance phase, which you will remain in indefinitely. In this phase, you include around 9 servings of carbs per day, or fewer than 125 grams of net carbs.

SUMMARY

The F-Factor Diet encourages eating three meals plus one snack per day. It starts by slowly increasing the number of net carbs you eat before reaching a weight maintenance eating pattern.

The F-Factor Diet emphasizes eating healthy, whole foods that are minimally processed, which can support a weight loss journey.

Foods recommended on the F-Factor Diet are also high in fiber, a nutrient known to help you achieve and maintain a healthy weight. Fiber is slowly digested, keeping you full for longer between meals (4, 5).

Decades of research have found a link between eating more fiber and losing weight, even preventing obesity and related chronic diseases (6, 7).

One study in 345 adults with excess weight or obesity found that fiber intake was the most significant dietary factor in promoting weight loss, regardless of calorie intake or the macronutrient composition of their diet (8).

SUMMARY

The F-Factor Diet is based on eating high fiber foods, a strategy that has long been associated with weight loss and other health benefits.

Though research on the F-Factor Diet specifically is lacking, its principles may offer several other potential health benefits, including:

• May improve your heart health. Research shows that high fiber diets can lower your LDL (bad) cholesterol and prevent atherosclerosis, the buildup of plaque in your arteries that can lead to heart disease (2, 9, 10).
• May lower your blood sugar. Foods that are higher in fiber tend to prevent blood sugar spikes and even lower your risk of type 2 diabetes (11, 12).
• May prevent constipation. Eating a high fiber diet can help increase the frequency and bulk of your stool, as well as promote bowel regularity (13).

As you can see, there are several other potential health benefits of following the F-Factor Diet, which mostly have to do with its significant fiber content.

SUMMARY

The fiber content of the F-Factor Diet offers other potential health benefits, such as improving heart health, lowering your risk of type 2 diabetes, and preventing constipation.

Despite the possible health benefits associated with the F-Factor Diet, some potential downsides should be considered before adopting this way of eating.

The F-Factor Diet minimizes the importance of exercise as part of your weight loss routine. It even goes so far as to say that exercise may increase your appetite, making you eat more and prevent weight loss.

Being physically active by doing things like running, walking, biking, yoga, weight lifting, or playing sports is beneficial for weight loss and overall health (14, 15).

Furthermore, the emphasis on fiber as the main nutrient could make you lose sight of other important nutrients in your diet. Though fiber is important, it’s not the only nutrient needed to maintain a healthy, sustainable weight.

For instance, protein and fat play integral roles in weight loss, as they can help keep you full for longer and increase the overall number of calories you burn (16, 17).

What’s more, eating large amounts of fiber at once can lead to bloating, cramping, gas, and even diarrhea. Though these are normal side effects that indicate fiber is doing its job, it may be best to increase your intake slowly if you’re not used to eating much fiber (2).

Also, during phase 1, the F-Factor Diet requires you to eat a specific brand of high fiber, appetite-control crackers called GG Bran Crispbread. The crackers are used in place of bread to keep you full for longer between meals.

These crackers, in conjunction with other recommended foods, would need to be reevaluated for people who are unable to consume wheat or gluten.

Furthermore, the price point of the F-Factor Diet can vary. The program’s annual revenue is reportedly over 1 million dollars, with a personal startup package with Zuckerbrot costing $15,000.

The good news is that you can likewise embark on the F-Factor Diet on your own for much cheaper, using Zuckerbrot’s books “The F-Factor Diet” and “The Miracle Carb Diet” as guidance. There are also many recipes available on the F-Factor Diet website.

SUMMARY

Though the F-Factor Diet has several potential benefits, it overlooks the importance of exercise and nutrients other than fiber as part of healthy weight loss and maintenance.

The F-Factor Diet outlines general guidelines regarding what to eat but leaves you with the flexibility to make your own choices.

It emphasizes many healthy foods like lean proteins, complex carbs, and high fiber, plant-based foods.

Here are some foods and beverages that would fit the F-Factor Diet guidelines:

• Whole grains: brown rice, quinoa, farro, millet, oatmeal, whole-wheat bread and crackers
• Beans and legumes: black beans, kidney beans, chickpeas, lentils, peas
• Nuts and seeds: nut butters, pumpkin seeds, cashews, walnuts, sunflower seeds, pistachios
• High fiber fruits: pears, oranges, apples, berries, bananas, dates
• High fiber vegetables: broccoli, carrots, beets, cauliflower, sweet potatoes, artichokes, avocados
• Lean proteins: eggs, chicken, fish, cottage cheese
• Beverages: water, alcohol

Note that although alcohol is permitted on the F-Factor Diet, it should only be consumed in moderation. This is defined as one drink per day for women and two drinks per day for men (13).

The F-Factor Diet also promotes its own line of powders and bars that offer a combination of protein and fiber for people looking for convenient snacks.

When eating out, the diet recommends skipping the extra dressings and oils, avoiding fried foods, choosing high fiber sides, ordering the appetizer portion of entrées, and replacing desserts with low calorie options like coffee.

SUMMARY

The F-Factor Diet emphasizes whole, minimally processed foods like whole grains, beans, legumes, nuts, seeds, lean proteins, and high fiber fruits and vegetables.

No foods are officially excluded on the F-Factor Diet.

However, highly processed foods and low quality carbs should be minimized for the best weight loss results. These include:

• Refined grains: white bread, pasta, crackers, white rice, biscuits, tortillas
• Processed foods: candy, potato chips, fast foods, french fries, baked goods
• Refined oils: canola oil, soybean oil, corn oil, hydrogenated fats
• Sugar-sweetened beverages: soda, fruit juice, sweet tea, sports drinks, energy drinks

Keep in mind that even though these foods don’t offer much in the way of nutrition or health benefits — and can even contribute to a higher risk of certain chronic diseases — the F-Factor Diet allows you to enjoy them on occasion if you want to (19, 20).

SUMMARY

Although no foods are off-limits on the F-Factor Diet, research shows that highly refined and processed carbs, oils, and sugar should be limited for optimal health and weight loss support.

Below is what 3 days of the F-Factor Diet may look like during the maintenance phase.

Day 1

• Breakfast: cottage cheese with almonds and raspberries
• Lunch: lean turkey and cheese sandwich on whole-wheat bread, with romaine lettuce, tomato, and avocado
• Dinner: whole-wheat pasta with flank steak, roasted artichokes, and a side of oranges
• Snack: banana with peanut butter

Day 2

• Breakfast: Greek yogurt with berries, hard-boiled egg
• Lunch: arugula salad topped with steak and chopped veggies
• Dinner: roasted chicken breast with peas, a side salad, and whole-wheat roll
• Snack: glass of milk with high fiber crackers

Day 3

• Breakfast: high fiber waffles topped with berries
• Lunch: mixed green salad topped with chopped veggies and tofu
• Dinner: zucchini noodles with tuna, spinach, tomatoes, and garlic
• Snack: apple slices with cashews

SUMMARY

The sample meal plan above includes some foods that would fit the maintenance phase of the F-Factor Diet, but you could adjust it based on your personal preferences.

The F-Factor Diet is a weight loss diet that emphasizes eating high fiber foods in combination with lean proteins. It allows you to eat at restaurants and doesn’t restrict any foods or beverages or require you to exercise.

Research on the F-Factor Diet specifically is unavailable, but the high fiber nature of the diet may promote weight loss and support overall health. It may even prevent constipation, support heart health, and help you manage your blood sugar.

However, the F-Factor Diet comes with some downsides to consider. It doesn’t regard exercise as a necessary part of a healthy weight loss journey and emphasizes fiber over all other nutrients.

While most people would likely benefit from eating more fiber, eating a variety of healthy, whole foods and following a lifestyle that works well for you may be the best option for sustainable weight loss.