Fast Bar Review – How Do These Nutrition Bars Compare?

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By Leslie Waterson

Reviewed by Juliana Tamayo, MS, RDN - Last Updated


Intermittent fasting is the latest new diet trend promoted to help with rapid weight loss. Intermittent fasting consists of an eating pattern that cycles through periods of fasting and eating. The point of intermittent fasting is no to control which foods you eat, but when you eat them. So it’s not so much a diet as it is an eating pattern. 

One of the hardest parts about intermittent fasting is keeping cravings down when you are in fasting periods. This makes sense after all; when you are starved for nutrients your body produces hunger hormones telling you to eat. 

Fast Bars are nutrition snack bars designed to curb the appetite to make periods of intermittent fasting more manageable. Fast bars contains a healthy blend of fats and nutrients that keep your metabolism going while in periods of fasting. Fast Bars also help curb appetite until your next meal or can even be used as a meal replacement while on something like a keto diet. If you are on a keto diet, make sure to stay in ketosis with the Lumen Metabolism Device.

There is quite a bit of evidence showing that intermittent fasting is pretty effective for short term weight loss, the long term health effects are not clear so we cannot comment too much on those. However, we can talk about Fast Bars and answer some important questions like the pros, cons, where to buy, and whether it is worth the purchase.

Fast Bar Nutrition Bars Eating

Overview: Fast Bars

Fast Bar Nutrition Bars Product

Fast Bars are made from a healthy selection of nuts that are made to help curb appetite when fasting. Nuts are particularly suited for this task because they contain high quantities of beneficial fats and protein, and have a very low carb count. This is also why they are so popular as a keto diet option. Fast Bars are made from a blend of nuts that work as a meal replacement or just as a daily snack. The creators recommend eating at least one bar a day around breakfast time or as a replacement for a meal. 

Keep in mind that Fast Bar is designed to support an intermittent fasting diet. This does not mean you can’t just eat them as a snack, but the creators claim they are most effective when integrated into an intermittent fasting pattern.  You should also keep in mind that this is a nutrition bar, not a protein bar. If you are looking for a great protein bar, we recommend checking out our Built Bar review to see why it’s our new favorite pick.

Each Fast Bar contains 21F of unsaturated fats, 5 grams of protein, and 14 carbs; only about 5% of the daily value. Each bar also has a substantial amount of fiber, calcium, and iron. All of their products contain tree nuts, so they are not for those with serious nut allergies. The products are vegan and soy-free, but they are made in a facility that processes soy, wheat, and egg products. That;t not incredibly important but it is still something to keep in mind. 


  • Good source of fats and proteins
  • Taste great
  • Suppresses appetite 
  • Good source of iron, calcium, and potassium


  • Not incredibly unique
  • Not safe for those with nut allergies
  • Somewhat expensive

Who Make Fast Bars?

Fast Bars are made by L-Nutra, a nutrition technology company that is focused on nutritional supplements to help with intermittent fasting. L-Nutra was founded in 2009 by Dr. Valter Longo who was inspired to make a product that can improve human health and longevity. L-Nutrapioneers technologies that mimic and enhance the effects of fasting to “unleash the body’s natural ability to fuel and rejuvenate itself and promote longevity.”

L-Nutra’s advisory board is made up of several MD and Ph.D. holders so they definitely have an air of legitimacy to their products. They claim that their Fast Bar products are the culmination of over 25 years of scientific research on fasting.

L-Nutra also makes ProLon, a fasting-mimicking diet program that can enhance performance, facilitate weight loss, enhance cellular renewal, and metabolic health. ProLon is also based on the same fasting research involved in the development of Fast Bars. 

How Do Fast Bars Work?

Fast Bar Nutrition Bars

Fast Bars work by giving the body a small supply of fats and proteins to keep the metabolism busy while fasting. The main ingredient in each bar is nuts which have good quantities of healthy fats and protein while having a low carbohydrate count. Fast Ba can be used while intermittent fasting or it can serve as a meal replacement or even just a snack when you are hungry. 

When the body does not have any food, it automatically slows metabolism to conserve energy. If you are trying to lose weight, this is bad. Fast Bars give your body a supply of nutrients that let your metabolism keep working and force you body to start burning fats to lose weight. Fast Bars also curb the appetite, making it easier to stick with your fasting schedule. 

Ingredients in Fast Bars

Fast Bar Nutrition Bars Ingredients

Virtually all the ingredients in Fast Bars are nuts, including macadamia nuts, pecans, and almonds. Most of the bars also contain honey as a nice low-sugar natural sweetener. 

Nuts, in general, are a great diet food as they have very low levels of carbohydrates and high protein and fat content. These two substances are the most important things for your body to have when fasting or doing some low carb-diet. Nuts are also very filling which cuts your appetite and reduces cravings. 

Safety and Side Effects

No ingredients in Fast Bars are natural and do not have negative side effects. Since they are made from tree nuts, those with tree nut allergies should stay away. 

Where to Buy and Cost

Fast Bar Nutrition Bars Website

You can buy Fast Bars directly on the company website. It does not seem to be available on Amazon or in physical retail stores as of now. 

Fast Bars: Are They Worth it?

Absolutely 100%. Fast Bars have some great ingredients that are 100% natural and known to be healthy. We are less certain about the health effects of fasting, but at the very least Fast Bars make a healthy snack option that is a good replacement for that bag of chips or cookies. 

Overall Rating:
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Leslie Waterson

Leslie has been passionately involved in the health and fitness industries for over a decade. She is constantly reviewing the latest scientific research and studies in order to take a research-backed approach to lifestyle optimization. Her main areas of interest include nutrition and supplementation. Leslie shares her findings on Fitness Clone to help other health enthusiasts choose the products and routines that will help them achieve their goals.

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