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The only bar your body doesn’t think it’s eating.
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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Randomized controlled study
Glucose flat. Ketones climbing. Still fasting.
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
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, built for every part of your 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
25+ years of fasting biology research in a bar.
Years of fasting biology research at USC
Physicians trust the Prolon platform
Clinical trials behind the broader Prolon protocol
Formulation tested in randomized clinical trials
Pick your flavor
Clinically proven. Three delicious flavors.
Available in 3 flavors + Variety Pack · 12 bars per box
The only bar clinically proven to keep you in a fasting, fat-burning state
Same patented fasting mimicking technology. Three flavors. Get the Variety Pack and try them all, or pick a single flavor on the product page.
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Questions
What people ask before their first box
No. In a randomized controlled study, the Fasting Bar produced glucose and ketone curves comparable to a water-only fast. It was engineered with the USC Longevity Institute to stay below the nutrient-sensing thresholds (mTOR, RAS, PKA) that switch the body into a fed state, so nourishment goes in while the fasting, fat-burning state stays intact.
Most snack bars are food the body clearly responds to, triggering the pathways that shift you out of a fasting state. The Fasting Bar was formulated around fasting physiology instead: low glycemic index, longevity nuts, complex carbohydrates and 6g of plant-based protein, dosed to stay below those signaling thresholds.
Whenever it fits your day. Use it in the morning in place of breakfast to extend your overnight fast, mid-day, post-workout or while traveling, or as a late-night swap that satisfies a craving without spiking glucose near bedtime.
The Fasting Bar has a low glycemic index and was designed not to spike glucose, which makes it a great option for people managing blood sugar, including diabetics. As with any dietary change, check with your healthcare provider about your individual situation.
Macadamias, walnuts and pecans are the headline ingredients, plus complex carbohydrates for steady absorption, 6g of plant-based protein, fiber, omega-3s, antioxidants, vitamins and minerals. It is plant-based, low glycemic, gluten-free, dairy-free, soy-free and keto-friendly.
Yes. It uses the same patented fasting mimicking technology developed by L-Nutra scientists with the USC Longevity Institute that powers the 5-Day program. The bar is the everyday format of that science, not a replacement for a full 5-Day cycle.
Have a bar. Keep the fast.
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% · 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.