The ketogenic diet has an array of health and performance benefits that I won't go into here but there are plenty of useful resources online. Traditionally it involves eating less than 5% of your caloric intake per day in carbohydrates, 20% from protein and 75% in healthy fats.
Essentially your body is forced to preferentially use fatty acids (or ketones) as a primary fuel source instead of glucose; the advantage to this is a "more efficient" utilisation of body fat during periods of calorie deficit or fasting.
One of the major attractions to a ketogenic diet other than the rapid body fat loss is the mental clarity and energy benefits. Consistently a "mental clearness" is reported by ketogenic dieters which is a major advantage at work; I have found it invaluable in medical school. A decrease in insulin spikes during the day also maintains a more constant energy level - no more mid-afternoon crash.
I have run a "modified" ketogenic diet for several years. Why modified? Personal experience has shown me that a slightly higher protein intake allows me to recover better from training. So my macronutrient breakdown might look something like this:
Total calories: 3,200 kcal
Fat: 240g (68%)
Protein: 210g (26%)
To get the most bang for my buck, I consume all of this between 13:00-21:00 each day. This leaves 18 hours for fasting when my body can start breaking down body fat stores for energy.
A strict ketogenic diet is difficult to sustain so every 2 weeks I allow a cheat day where anything goes - pizza, donuts, burgers, fries, etc. At the beginning of the day you'll love it because it is guilt free eating, you've earned it; but by the end of the day, you'll be sick of eating junk until the next cheat day rolls around.
A high fat diet might seem difficult to implement or simply shop for, so here are some staple food to get you started:
Coconut Oil/MCT Oil
Cheese (preferably blue)
70%+ Dark Chocolate (Higher % = better)
Whole Eggs (..again)
Fatty Fish (Salmon)
Carbohydrates (use sparingly):
Other leafy greens
Frank's Hot Sauce
Full Fat Mayo
Zero sugar/calorie syrup
Say No To:
This is just some basics to get you started. YouTube and other online resources have a variety of keto foods and recipes.
As always, be smart and do your own research and give whatever you're doing maximum effort.