The 5:2 diet is based on a principle known as intermittent fasting (IF) – where you eat normally for five days a week and fast on the other two days. On top of losing weight, fans claim the 5:2 diet can improve lifespan and brain function, and protect against conditions such as dementia and Alzheimer's.
However, evidence on the effectiveness of the 5:2 diet is limited when compared with other types of weight loss techniques. One 2010 study found women placed on a 5:2 diet achieved similar levels of weight loss to women on a calorie-controlled diet, and were also less likely to develop chronic diseases such as type 2 diabetes. There is some evidence that the 5:2 model may help lower the risk of certain obesity-related cancers, such as breast cancer.
The paleo diet, also known as the caveman diet, was Google's most searched-for weight loss method in 2013. The diet consists of foods that can be hunted and fished – such as meat and seafood – and foods that can be gathered – such as eggs, nuts, seeds, fruits, vegetables, herbs and spices. It's a regime based on the supposed eating habits of our hunter-gatherer ancestors during the paleolithic era, before the development of agriculture around 10,000 years ago. That means cereal grains including wheat, dairy, refined sugar, potatoes and salt – as well as anything processed – are strictly off the menu. There is no official "paleo diet", but it is generally seen as a low-carb, high-protein diet, with some variations on carbohydrate and meat intake. Advocates say the paleo diet is a long-term healthy eating plan that can help you lose weight and reduce your risk of diabetes, heart disease, cancer and other health problems.