I believe it completely. This was one of the first effects I felt, before I had gotten deep into the literature. I remember after being on keto for a week, I was walking through a parking lot, and all of a sudden it was like my head popped through the clouds. I had a sudden burst of energy, my anxiety dropped, and I felt like skipping to the car. The keto flu disappeared, and I felt HAPPY for the first time in years. All in the course of 5 minutes. Over the next few weeks, I realized this had extended to my work as well: I felt focused, clear-headed, and able to work more quickly than I had in years. I used to get 1-2 migraines per month. I haven't had one in two years. I started the diet for weight loss (70 lbs now), unaware of the other benefits. It turns out this is starting to be supported by literature, though it is still a new area of study.
I started this because of my work in the pediatric epilepsy department I worked in. Nearly all of the kids that came through were put on a very low carb diet; it significantly reduced or eliminated the seizures in about 60%+ of the cases. Naturally, I wondered what was going on. It turns out that there are a number of neurological benefits. It has been shown to treat bipolar disorder [1], schizophrenia[2,3], ADHD[4], and so on. A lot of these are small studies. I am fine with that. If you have a patient who has been schizophrenic for 50 years, and no medication has worked, then a dietary change reverses most symptoms in a week, I feel comfortable saying something significant is happening, even with N=1. (A few years back at a Society for Neuroscience meeting, some NIH director made the point that if I say I have engineered a flying pig with wings, and bring it out on stage as proof, it doesn't make sense to say repeat it 10 or 100 times; the proof is sitting in front of you!). I have only cheated twice in two years, and both times I was groggy for days, and felt the depression creeping back. I realized this was how I ALWAYS felt previously.
I started this because of my work in the pediatric epilepsy department I worked in. Nearly all of the kids that came through were put on a very low carb diet; it significantly reduced or eliminated the seizures in about 60%+ of the cases. Naturally, I wondered what was going on. It turns out that there are a number of neurological benefits. It has been shown to treat bipolar disorder [1], schizophrenia[2,3], ADHD[4], and so on. A lot of these are small studies. I am fine with that. If you have a patient who has been schizophrenic for 50 years, and no medication has worked, then a dietary change reverses most symptoms in a week, I feel comfortable saying something significant is happening, even with N=1. (A few years back at a Society for Neuroscience meeting, some NIH director made the point that if I say I have engineered a flying pig with wings, and bring it out on stage as proof, it doesn't make sense to say repeat it 10 or 100 times; the proof is sitting in front of you!). I have only cheated twice in two years, and both times I was groggy for days, and felt the depression creeping back. I realized this was how I ALWAYS felt previously.
[1]http://www.ncbi.nlm.nih.gov/pubmed/11918434 [2]http://www.ncbi.nlm.nih.gov/pubmed/26547882 [3]http://www.ncbi.nlm.nih.gov/pubmed/19245705 [4]http://pediatrics.aappublications.org/content/129/2/330