Yo-yo effect

The yo-yo effect (weight cycling) is repeatedly losing weight on a highly restrictive diet, then regaining it — sometimes past the starting weight — once the diet stops. Whether it causes lasting metabolic harm is still debated.

The yo-yo effect (weight cycling) is repeatedly losing weight on a highly restrictive diet and then regaining it — sometimes past the starting weight — once the diet is dropped. Underneath it is usually a deficit too aggressive to sustain long-term, followed by a return to old habits.

Whether this cycle causes lasting metabolic harm is still debated among researchers: Sanaya and colleagues’ 2024 review, published in Current Obesity Reports, found that most current evidence doesn’t support that claim. Cookrange’s adaptive planning approach aims to offer a sustainable target instead of the extreme restriction that tends to trigger the cycle in the first place.