Get fasting
benefits with five days of real food.
Eat every day of your fast. The Prolon 5-Day Fasting Mimicking Diet (FMD) supports fat-focused weight loss while helping protect lean muscle.
4.4 out of 5
customer rating
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40+
clinical trials
25+
years of research
130+
global patents
Recommended by over 20,000 healthcare professionals.
Fasting benefits. Food included.
Prolon’s 5-Day Fasting Mimicking Diet is designed to keep your body in a fasting state while you eat.
Eat every day
Soups, bars, olives and more, portioned for five days.
A precise nutrient balance
Plant-based foods, limited in calories, protein, and sugar, with healthy fats.
Support a fasting response
Formulated to stay under your body's nutrient-sensing pathways.
Follow each day’s box and meal guide.
Autophagy, explained
Autophagy is how your cells remove and recycle old, damaged parts.
The 5-Day is designed to support this process while you eat. It is the only nutrition program clinically proven to trigger autophagy in humans.
Open the box. Follow the guide. Eat what's there.
Open the box. Follow the guide. Eat what's there.
1
Open the box for the day
Each numbered box includes that day's pre-portioned foods.
2
Follow your meal guide
Follow the day's meal plan.
3
Ease back in on Day 6
Your Day 6 guide shows how to return to regular meals with your own food.
HSA/FSA Eligible
Free shipping over $200*
Ships in 3 to 5 business days
Five days of plant-based
food, already portioned.
Plant-based
Gluten-free
Dairy-free
Soups
Mix-and-heat soups like minestrone and tomato. Ready to eat with Next Gen.
Nut bars
Cold-pressed with almonds, macadamia and pecans.
Olives and kale crackers
Snacks, portioned for each day.
Herbal teas
Caffeine-free, to help you stay hydrated.
L-Drink
For Days 2 to 5, designed to support hydration and help protect lean muscle.
Supplements
A daily supplement with multivitamins, minerals and omega-3.
Plant-based
Gluten-free
Dairy-free
See what’s in the box.
Choose your kit
Select Your Kit:
Original
Bold flavors
Expanded Variety
Next Gen
Ready-to-eat organic soups. Follow your kit’s daily meal guide for all five days.
Every kit is five days of plant-based food, already portioned, with group coaching through all five days.
Prolon 5-Day FMD — Next Gen
Rated 4.4 out of 5
Plan
Subscribe and save 15%
Welcome Kit
Worth $45
Water bottle, Fasting Shake, 3 Fasting Bars and L‑Protein, with your first delivery.
Free shipping on every delivery
Pause, skip or cancel anytime
Deliver every
Monthly is recommended for your first three cycles.
One-time purchase
Free shipping
HSA/FSA eligible on qualifying one-time orders
Subscribe and save 15%
Welcome Kit
Worth $45
Water bottle, Fasting Shake, 3 Fasting Bars and L‑Protein, with your first delivery.
Free shipping on every delivery
Pause, skip or cancel anytime
Deliver every
Monthly is recommended for your first three cycles.
HSA/FSA Eligible
Ships in 3 to 5 business days
Your 5-Day program.
Day 1
Ease into your fast
Your body adjusts to fewer calories as you begin fasting with food.
Day 2
Fat-burning begins
Your body begins using fat for fuel and may enter ketosis. From today through Day 5, L-Drink helps protect lean muscle.
Day 3
Autophagy: the body’s cellular clean-up
Your cells begin clearing out damaged components.
Day 4
Autophagy and fat‑burning in full swing
The clean-up continues. This is when many users report peak mental clarity.
Day 5
Cellular renewal
After the 5 days, your cells begin functioning as younger, healthier versions of themselves.
Day 6: ease back into regular meals
Start with small, light meals. Follow the transition guide for suggestions.
Developed from 25+ years of research at the USC Longevity Institute.
The 5-Day is grounded in the research of Dr. Valter Longo. Here is what clinical studies measured.
Fat-focused weight loss
5.7
lb
average weight loss
over 3 months
One 5-Day cycle each month.
In a randomized study, adults lost weight and body fat after three consecutive monthly cycles.
Your cells' natural clean-up
Autophagy
The only nutrition program clinically proven to trigger autophagy in humans.
Skin hydration
Increases skin hydration by 25% after three consecutive monthly cycles.
Targets visceral fat
The dangerous fat that surrounds your organs. Visceral fat can be reduced after one 5-Day cycle.
Muscle support
Water-only fasting can reduce lean mass along with weight. The Prolon 5-Day includes L-Drink to help protect muscle.
“I love the science supporting Prolon, and I love that the science has been published in multiple peer-reviewed journals.”
Dr. Joel Kahn, Cardiologist
HSA/FSA Eligible
Free shipping over $200*
Ships in 3 to 5 business days
How the Prolon 5-Day compares
Prolon 5-Day
Water-only fast
Daily eating window
Food
Provided food
No food
Your meals
Timing
5 days
You decide
Every day
Guidance
Group coaching and daily meal plan
On your own
On your own
What customers say
Rated 4.4 out of 5
Better than I expected
“The olives and the nut bar were small things that made a big difference. It never felt like I was staring at an empty plate.”
Cassandra R.
Thorough and well explained
“The guide answered every question before I had to look anything up.”
Ana L.
Great product!
“This is my 5th Prolon kit. It's such a great way to do a fast - and I don't have to worry about my choices because it's all picked out for me!”
Stephanie L.
Individual experiences vary.
Five days, from people who've done it
Peter Weber
Julia
Kelly
What if I get hungry?
Some people may feel hungry at some points, especially during their first cycle (users report it gets easier with each round), and that’s normal - but staying hydrated helps!
Try plain sparkling water or caffeine-free herbal tea for cravings, or ask for other suggestions in your coaching group.
Get support through all five days.
Your kit includes a group led by a longevity dietitian. Choose a week and register on the coach-led fasting group page.
Before you start
Get ready with a live prep call.
During your fast
Daily Zoom sessions, practical tips and Q&A.
Back to regular meals
Get help with your Day 6 transition.
Can't join live? Watch the recordings.
FAQs
How can I eat and still get fasting benefits?
The FMD uses foods precisely formulated to stay under nutrient-sensing pathways, so your body thinks it is fasting.
What results should I expect?
The 5-Day supports fat-focused weight loss while helping protect lean muscle. Results vary. The 5.7 lb study average was measured after three consecutive monthly cycles.
How often should I do the program?
Start with three consecutive monthly cycles, followed by three to four cycles yearly to help maintain and optimize results long term. Ask your healthcare practitioner what is right for you.
Is the 5-Day right for everyone?
The Prolon 5-Day is a food-based nutrition program, not a medication. It is intended for use by healthy individuals who want to support their health and wellbeing, and by overweight individuals who want to proactively manage their weight in a healthy way. If you are on medication or have a pre-existing medical condition, consult your healthcare practitioner before beginning.
What's the difference between the kits?
Original and Bold flavors have powdered soups. Expanded variety includes a shake. Next Gen has ready-to-eat organic soups. Select each kit under Choose your kit to read what’s inside.
How does Subscribe and save work?
Choose delivery every 1, 2, 3 or 4 months in the buy box. Your subscription renews automatically. You can pause, skip or cancel. Make changes at least 24 hours before renewal.
Can I use HSA/FSA funds?
Check eligibility through Sika Health for a one-time order. Subscriptions are excluded. Use guest checkout, select Sika and complete the health survey.
What about shipping?
Orders ship in 3 to 5 business days. Continental US orders over $200 get free shipping. Subscription deliveries also ship free. Checkout shows taxes and any shipping charges.
Does the kit contain nuts?
Yes. Every kit contains tree nuts (almonds, macadamia, pecans, coconut) and may contain soy. Check the ingredient and nutrition labels for your kit before ordering, and ask the team about any allergy or dietary restriction.
Can I have coffee?
You can have one 8-ounce cup of plain black coffee a day, with nothing in it.
Can I exercise?
Keep activity light during the program.
How many cycles are in one kit?
Each kit contains one 5-Day cycle.
I've stopped taking a GLP-1. Is the 5-Day for me?
Ask your healthcare practitioner about the 5-Day after stopping a GLP-1. Follow their guidance on medication and nutrition.
Start your five days of fasting with food.
Your food, meal guide and group coaching are included.
HSA/FSA Eligible
Free shipping over $200*
Ships in 3 to 5 business days
Keep Skin Soft
Both tallow jars . 91