People on diets often experience a plateau after their initial weight loss when their weight stubbornly refuses to go down any further. A study of 11 fat men on a diet found that losing around 10% of their body weight slowed down their metabolism (meaning they burnt up less calories) and made them more hungry. The men showed increased 'cognitive dietary restraint' and their mental and physical health remained unchanged. Their risk of depression had significantly increased compared to before their weight loss. The researchers called for 'caution and reasonable objectives when prescribing a weight reduction programme for obese individuals'
Chaput, Jean-Philippe ... [et al] - Psychobiological effects observed in obese men experiencing body weight loss plateau Depression and Anxiety 24(7), 518-521