Circadian timekeeping allows for the appropriate temporal regulation of metabolism to anticipate and respond to recurrent daily changes in the environment. Dysregulation of this system is increasingly recognised as a contributing factor in the development of chronic diseases associated with aging. Current dietary guidelines emphasise the importance of consuming a variety of foods from core food groups, and promote energy restriction (ER). However, recommendations on when to eat are not included in public health advice, or in the clinical management of individuals at risk of, or with, type 2 diabetes or obesity. This is a significant omission to address. While moderate, daily ER delays the onset of aging-related pathologies in mice, what researchers haven’t considered is that mice placed under ER eat their entire daily food allowance within 2 - 4 hours. As such, they have not distinguished the benefits of ER from those of time restricted eating (TRE) patterns, self-imposed by the animals. Meanwhile, recent studies by our group, and others, have established that ER restores circadian variation, protecting mice from the metabolic consequences of aging and obesity, without reducing food intake. In humans, pilot studies suggest that TRE improves glycaemic control, but modest weight losses are usually co-observed. Eating earlier in the day is also associated with greater weight loss and improvements in glucose control. However, late or early TRE protocols are both showing promise to improve metabolic health, albeit with greater weight effects when meals are consumed earlier in the day. Macronutrient timing may also be important in this response.