How do mood and sleep change during contest prep?

Short answer

Both get worse. During prep, bad-mood scores rose 15 to 35% and sleep-problem scores rose 26%, with the worst near the end. But both returned to normal within 12 weeks after the show.

How do mood and sleep change during contest prep?
'Less body fat → worse mood and sleep' — does this formula hold?
A common belief: contest prep makes you irritable and wrecks your sleep. We checked how much months of eating less and training more change mood and sleep, and whether they come back after the show.
Mood clearly got worse
Vigor down 20%, fatigue up 23%
Comparing 20 competitors in the off-season and during prep: during prep they cut calories by about 45% and lost 9% of their body weight. Vigor scores dropped 20%, fatigue rose 23%, and overall bad-mood scores rose 35%. Stress scores also rose 34 to 50%.
Sleep got worse too
Sleep-problem scores rose 26% right before the show
A 2026 study followed 19 competitors (8 men, 11 women) from about 21 weeks out. 1 to 2 weeks before the show, sleep-problem scores were 26% higher than at the start. Bad-mood scores rose about 15% over the same period. Strength stayed about the same.
Felt sleep and measured sleep differed
A wrist tracker showed almost no change
A study measured 1 competitor every month through 8 months of prep. Sleep quality as he felt it got worse, but sleep measured by a wrist tracker barely changed. An analysis of case studies covering 15 competitors found the 2 whose sleep was assessed both reported worse sleep. What got worse was sleep as people felt it, more than sleep as measured.
When is it worst?
Mood swung most in the last 2 months
In the analysis of case studies, the 2 that tracked mood both found bad-mood scores rising during the 2 months before the show, along with less energy and more fatigue. Another case that followed 1 competitor found mood was stable until month 5, then swung.
And after the show?
Mood and sleep were back to normal within 12 weeks
In the same 19-person study, 12 weeks after the show both bad-mood and sleep-problem scores were back to pre-prep levels. Scores for worry and fixation about food peaked during prep and fell from 7.9 to 3.6 during recovery. A case that followed 1 competitor for a year saw his bad-mood score rise from 6 to 43, then return to 4 six months later.
Bottom line: it gets worse, then it comes back
Mood 15 to 35% worse, sleep 26% worse
During prep, bad-mood scores rose 15 to 35% and sleep-problem scores rose 26%, with the biggest swings near the end. Sleep measured by a wrist tracker barely changed; what got worse was how sleep felt. Mood and sleep returned to normal within 12 weeks after the show.