By Lily Hautau, CNN
(CNN) — Five requirements. Seventy-five days. No breaks and no room for mistakes.
That’s the premise of 75 Hard, a challenge created by entrepreneur and author Andy Frisella and marketed as a “transformative mental toughness program” and “an ironman for your brain,” according to his website.
Chicago runner Sarah Lyons learned quickly how demanding the rules could be.
On paper, the daily checklist seems straightforward: Follow a structured diet with no alcohol, drink a gallon of water, read 10 pages of nonfiction, take a progress photo, and complete two 45-minute workouts, one outdoors, every day for 75 consecutive days.
In practice, the routine can take over your schedule and your life.
The challenge includes several healthy habits such as daily movement, reading and hydration, but experts say its rigid, all-or-nothing approach may undermine the long-term behavioral changes it promises.
For people drawn to 75 Hard, the goal shouldn’t be perfection but building habits you can keep when life inevitably gets messy, according to experts. Here’s what they say should be taken away from this challenge — and what could be left behind.
The ‘start over’ rule
One of the program’s defining features is its strictness: Miss one task and you restart the entire challenge, whether you’re on day 2 or day 74.
The website discourages modifications, saying that “compromise nerfs off the sharp edges of what could be an exceptional life.”
Before she started her first 75 Hard challenge, Lyons “felt stuck in a rut both physically and mentally.” Initially drawn to the structure of the challenge, she was looking for something to help rebuild discipline and momentum.
But that structure can backfire.
“Sustainable fitness isn’t about punishment or proving discipline through extremes — it’s about building habits that integrate into your lifestyle in a way that feels supportive and repeatable,” said CNN fitness contributor Dana Santas, a certified strength and conditioning specialist and mind-body coach in professional sports.
Forcing a restart after one deviation, Santas said, can reinforce a cycle of perceived failure rather than building durable behavior changes — especially when real life inevitably intervenes through travel, illness, family obligations, weather or simply an off day.
That mindset may also affect eating behaviors. It can contribute to binge eating, disordered eating patterns, negative body image and negative self-talk, warned Bethany Doerfler, senior clinical research dietitian at Northwestern Medicine Digestive Health Institute in Chicago.
People may also define “slip-ups” differently, she added, creating a potential gateway to unhealthy behaviors.
Lyons said the rigidity sometimes created stress in her own life, too. During her first attempt, she said there were many days when she delayed tasks until late in the evening, which added pressure rather than making her feel healthier.
With that strict framework in mind, experts say it’s worth separating the challenge’s healthier building blocks from the parts that may be risky or unsustainable.
One important note: Before beginning any new exercise program, consult your doctor. Stop immediately if you experience pain.
The diet: Flexible in theory, hard in practice
One element of the 75 Hard that does allow flexibility is the way people eat. Participants choose their own diet. That could mean Mediterranean, Paleo, cutting ultraprocessed foods or another structured approach.
But experts stress that any diet change works best when it’s designed for real life.
If you’re considering a structured eating p