Step one, which lasts two weeks and is described as the most restrictive phase of the diet, is supposed to “jump-start” your weight loss. The “average caloric intake is anywhere from 900 to 1,100 calories per day,” Zuckerbrot explains in The F-Factor Diet book. To stay under 35 grams of net carbs a day, you are permitted three serving sizes of specified high-fiber carbs. You can also eat “as many non-starchy vegetables as you like, and 2 to 6 ounces of lean or very lean meat or meat substitute” per meal, according to the book. However, “unrestricted” non-starchy veggies must be “raw, plain or steamed with no oil,” according to the site. And the list of foods to avoid in step one is pretty long: bread, cereal, grains, beans, peas, lentils, pasta, rice, pastries, crackers, most snack foods, baked goods, corn, peas, sweet potatoes, potatoes, yams, fruit juice, medium- and high-fat meats, and all dairy except for plain and nonfat Greek yogurt, Icelandic yogurt, or quark (which count as lean proteins).
Step two allows for a wider variety of foods and three additional servings of carbs (15 grams each). This raises the built-in calorie cap by about 240 when you add in accompanying calories from the increased protein and fat to go along with step two’s higher carb intake. The idea is that this calorie increase will prevent your body from thinking it is starving and potentially slowing down your metabolism (which would impede weight loss), the book explains. You remain on step two until you reach your intended “goal weight.”
In step three, you begin the “maintenance phase” that you stay on for the rest of your life. Along with getting three more additional servings of carbs, you’re allowed to eat a small serving of just about anything as long as you continue to stay within the carb and fiber parameters. (“Even a small portion of pasta…isn’t going to get you into trouble,” the intro to step three reads.) And even in the maintenance phase, the diet recommends curbing the intake of certain highly nutritious foods because “there is a difference between healthy and healthy for weight loss,” according to the site. That includes satiating and calorie-dense fats like olive oil, avocados, nuts, and seeds. Similarly, the diet favors low-fat and skim versions of dairy products and calls out ancient grains (like quinoa) for being detrimental to weight loss. “Essentially, the health benefits of ‘health foods’ can be outweighed (pun intended) if they’re so caloric that they cause us to gain weight,” as the page on ancient grains reads.
To meet the dietary requirements and keep weight loss (and weight maintenance) on track, followers are encouraged to consult the F-Factor app or book for recommended foods and portion sizes, and record all of their food and macronutrient intake via food journaling or the app. The company also sells an Intentions Bracelet that is meant to serve as a “daily visual reminder to honor your intentions for looking and feeling your best so that you never settle for mediocrity”—in other words, to apparently help you avoid making food choices that could prevent weight loss or cause weight gain. The packaging tells you to wear the bracelet on the wrist of your dominant hand: “This is the hand that holds the fork, reaches for the bread basket, or dips into the candy dish,” it reads. “This is the hand that will either undermine your intentions or honor them.”
What concerns some R.D.s about diets like F-Factor
The R.D.s we talked to had concerns about various aspects of the F-Factor diet, mostly surrounding what they saw as its restrictiveness and its emphasis on fiber. We grouped what they said into four main critiques.
1. They can be restrictive and hard to follow.
The F-Factor diet is a great example of “diets [that] parade around as an example of ‘liberation’ and ‘flexibility,’ when they are anything but,” Rachael Hartley, R.D., certified intuitive eating counselor and owner of Rachael Hartley Nutrition, tells SELF. “This way of eating is extremely restrictive,” Shana Minei Spence, M.S., R.D.N., C.D.N., founder of The Nutrition Tea, tells SELF. And “the more restrictive a diet is, the less likely it is that people will find it sustainable.” In response to the claim that F-Factor is restrictive and may not be sustainable, a company representative says, “F-Factor’s message is not about restriction, but rather the focus is on adding fiber-rich foods into your diet for fiber’s medically proven health and weight management benefits. From Day 1, F-Factor encourages breakfast, lunch, snack, and dinner and discourages skipping any meals.”