had a less developed hippocampus section of the brain

A link between a high protein Atkins diet and a significantly reduced brain mass has been identified by scientists. The study which was done on laboratory mice resulted in those mice following the Atkins diet having brains which were on average five percent lighter than mice who were fed diets with larger amount of carbohydrates. They also noted that the high protein laboratory mice had a less developed hippocampus section of the brain which is used for memory.

Ukmedix News has published research which shows that certain unhealthy diets can aggravate dementia illnesses such as Alzheimer's but this research goes one step further.
The mice which were used for the experiment had been specially bred so that they would develop Alzheimer's disease and were fed a whole range of different diets. 

The four different eating plans were either a regular diet, one with a high fat and low carbohydrate content, one with a high protein and low carb content and lastly a high carb and low fat option. The mice were regularly checked for their body weight and their brain weight as well as whether there was a buildup of plaque that is linked to Alzheimer's disease.

One of the scientists who took part in the study, Professor Sam Gandy from The Mount Sinai School of Medicine based in New York explained that the loss of brain mass associated with the high protein and low carb diet was a considerable surprise to him and the rest of the team. The researchers also saw that the mice on high fat diets had increased amounts of plaque buildup but this did not seem to affect them. The research is published in full in the medical journal Molecular Neurodegeneration.

High protein diets which are considered to be an effective and quick way of losing weight have been criticised because they are not balanced enough and therefore have been linked to a higher risk of heart attacks and kidney problems. However at the same time because they are so good at regulating excess body fat which in itself is bad for health they can often be justified overall.

Ukmedix News has also published research on more than one occasion that links a healthy Mediterranean low calorie diet full of vegetables, fruits and fish with a reduced risk of dementia and Alzheimer’s.