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New · Prolon Fasting Bar
The only bar clinically proven to keep you in a fasting, fat-burning state
Clinically formulated to nourish without breaking your fast. Blood sugar doesn't spike. Fat burning continues. Your body keeps doing the work, while you eat something that tastes like a treat.
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★★★★★
4.4 Stars
1M+ happy healthy customers
25+ Years of Research
Randomized controlled study
Same glucose. Same ketones. As drinking water.
In a randomized controlled study, the Fasting Bar produced glucose and ketone curves comparable to a water-only fast. Your body stays in the same physiological state. The bar is just along for the ride.
The shift
Most snack bars are food the body responds to; a response that can age the body by triggering certain pathways. This bar is engineered to stay below those pathways - the body thinks it is in a fasting state, even while you eat something.
Five reasons it works
The only bar built around fasting physiology
It avoids the three pathways that break a fast
mTOR
RAS
PKA
When you eat, three cellular nutrient-sensing pathways switch on and tell the body to shift into a "fed" state. The Fasting Bar was engineered, in collaboration with the USC Longevity Institute, to stay under those thresholds.
The result: nourishment goes in, the fasting state stays intact.
Glucose doesn't spike, ketones keep climbing
In a randomized controlled study, the Fasting Bar tracked the same glucose and ketone curves as a water-only fast. Low glycemic index, no spike, no detour out of fat-burning.
The takeaway: the body responds to it like water, not like a meal.
A breakfast that extends your overnight fast
Skipping breakfast has been associated with poor health outcomes. Morning nourishment supports vital organ function, including for the brain, heart, and muscles, and helps support a healthy metabolism and weight. The Fasting Bar delivers that morning nourishment, when the circadian rhythm calls for it, without ending your fasting, fat-burning window.
Why it works: macadamias, walnuts, and pecans deliver healthy fats aligned with brain composition, plus 6g plant-based protein for steady energy - all while keeping you in a fasting state..
A smarter late-night swap
Late-night snacking is linked to higher blood sugar, weight gain, and disrupted repair. Cookies, chips, and ice cream feed the body when it needs to be cleaning up, not storing more.
Swap it in: a Fasting Bar after dinner satisfies the craving without the glucose spike. A smarter alternative when you're managing weight and blood sugar.
Built from the nuts longevity research keeps pointing to
Macadamias, walnuts, and pecans are the headline ingredients. Research published in the New England Journal of Medicine linked eating nuts seven or more times per week with roughly 20% lower mortality from any cause.
What's inside: Packed with longevity nuts, complex carbohydrates for steady absorption, 6g of plant-based protein, fiber, omega-3s, antioxidants, vitamins, and minerals.
Five ways to use it
One bar, part of every day
Morning nourishment
Use in place of breakfast, or to extend your overnight fast.
Anytime snack
Mid-day, post-workout, or traveling. An on-the-go option that doesn't undo your day.
Late-night swap
For late-night cravings, satisfy without spiking glucose near bedtime.
Blood-sugar friendly
Low glycemic index. A great option for those managing blood sugar, including diabetics.
Weight management
A satisfying, low-glycemic option that supports weight management goals, for fasters and non-fasters alike.
The science behind it
How can eating food mimic fasting?
It seems counterintuitive. Fasting means not eating. But the body doesn't respond to food based on calories alone. It responds to signals.
When you eat, nutrient-sensing pathways like mTOR, IGF-1, and PKA activate and tell the body that nutrients are abundant. The body shifts into a "fed" state focused on growth and storage.
During fasting, those same pathways quiet down. The body shifts into fat utilization, cellular cleanup, and metabolic reset.
L-Nutra scientists, in collaboration with the USC Longevity Institute, researched exactly how much, and what type, of nourishment was needed to stay below those signaling thresholds. The Fasting Bar is the result.
The lineage
Same fasting mimicking technology as the 5-Day program. From the same labs
25+
Years of fasting biology research at USC
20K+
Physicians trust the Prolon platform
47+
Clinical trials behind the broader Prolon protocol
Patented
Formulation tested in randomized clinical trials
★★★★★
1M+ Happy Healthy Customers
+ FREE Welcome Kit
★★★★★
4.4 Stars
1M+ Happy Customers
Prolon 5-Day Fasting Mimicking Diet
A five-day program clinically formulated to target fat, protect muscle, and reset your body from the inside.
Designed to target fat and protect lean muscle mass
The only nutrition program shown to trigger autophagy in humans
No drugs, no injections, no long-term food deprivation
Plant-based: soups, nut bars, olives, kale crackers, herbal teas
HSA/FSA eligible · 90-day money-back guarantee
That's roughly what you'd spend on meals for the week anyway.
Choose your flavor:
The original powdered soups in familiar flavors: Minestrone, Tomato, Mushroom, Vegetable, and Minestrone Quinoa.
Choose your offer:
Starting at
+ Free Welcome Kit · HSA/FSA Eligible
One cycle is 5 days. Most customers run three to four cycles per year.
Patented Formula
Clinically Tested
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Questions
What people ask before their first box
Will the Fasting Bar break my fast?
No. In a randomized controlled study, the Fasting Bar produced glucose and ketone curves comparable to a water-only fast. The formulation was specifically designed to stay below the body's nutrient-sensing thresholds, so a fasting state stays a fasting state.
How is this different from a regular protein bar or snack bar?
Standard bars are formulated for taste and calories. They trigger the nutrient-sensing pathways (mTOR, RAS, PKA) that tell the body it's eating. The Fasting Bar was engineered in the opposite direction: nourish without flipping those switches. The result is a clinically tested, patented formulation that the body responds to like water.
When during a fast should I eat it?
A common approach is around hour 12 of a 16-hour fast for energy support and morning nourishment. The Fasting Bar works any time during a fasting window without ending it. It can also be used outside fasting as an everyday snack.
Is it safe for people managing blood sugar or diabetes?
The Fasting Bar is low on the glycemic index and clinically shown not to increase blood sugar. Many people managing blood sugar use it as a snack that does not produce the typical glucose response. As always, talk to a clinician about decisions specific to your care.
What is it made of?
Macadamias, walnuts, and pecans (the "longevity nuts"), complex carbohydrates for steady absorption, and 6g of plant-based protein. Gluten-free, dairy-free, soy-free, keto-friendly, plant-based. Antioxidants, fiber, vitamins, minerals, and omega-3s included.
Is it related to the 5-Day Prolon program?
Same fasting mimicking technology, same labs. The 5-Day program is a structured five-day protocol, while the Fasting Bar is the everyday format of the same science, built to fit into a normal week.
Eat. Stay in the fasting state
The first bar engineered to do both. Now shipping in three flavors and a Variety Pack. Subscribe & Save 15% on every order.
Shop & Save 15%
Subscribe & Save 15% · 90-day guarantee · HSA/FSA eligible
© Prolon · L-Nutra. Patented fasting mimicking technology developed with the USC Longevity Institute.
These statements have not been evaluated by the FDA. Not intended to diagnose, treat, cure, or prevent any disease.