WHEL (Women's Healthy Eating and Living)
Three thousand breast cancer survivors were coached for years to eat far more vegetables, fruit and fibre. They did, and it made no difference to recurrence or survival.
WHEL randomised 3,088 women (1995-2000) and followed them for a mean 7.3 years. The intervention group substantially and durably changed their diet (vegetables +65%, fruit +25%, fibre +30%, fat -13% at four years, confirmed by plasma carotenoids). Invasive breast cancer events (16.7% vs 16.9%) and deaths (10.1% vs 10.3%) did not differ. Secondary analyses generated hypotheses later explored elsewhere: women with both high vegetable-fruit intake and high physical activity had lower mortality; a nightly fast under 13 hours was associated with recurrence. WHEL and WINS (low-fat diet, marginal effect confined to HR-negative disease) are the reason the field moved from diet alone to energy balance, weight loss and exercise, and they are a standing caution against assuming observational diet associations are causal.
- 16.7 vs 16.9 out of 100 alive without the cancer coming back with Dietary intervention compared with Comparison; 0.2 fewer per 100.
- On this measure the first group did worse, not better.
- Put another way, the treated group had about 4 percent lower chance of the event at any given time (hazard ratio 0.96, likely range 0.8 to 1.14).
- The likely range for the hazard ratio crosses 1, so the difference could be due to chance.
- This endpoint is not one of the standard survival or response measures; read it alongside the trial's primary result.
- These results apply to the people the trial enrolled: Early-stage breast cancer survivors within 4 years of diagnosis: intensive telephone counselling for a diet very high in vegetables, fruit and fibre and low in fat vs printed dietary guidelines. People in a different situation may not see the same effect.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
3,088 participants enrolled.
| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Invasive breast cancer event (recurrence or new primary)primary | Dietary intervention | 1,537 | 16.7% | 0.96 (0.8–1.14) | — | link |
| Comparison | 1,551 | 16.9% |