Helps you save time in the kitchen
Meal prepping to ensure you have keto-friendly foods all week can take up a big chunk of your time. This is especially true for those who are on a clean keto diet and have food sensitivities or intolerances (dairy, food additives like MSG, etc.) since they need to be extra careful with ingredients.
Experienced keto dieters may find the idea of cycling OMAD with their usual eating pattern great for their schedule. As a bonus, it saves money on grocery shopping.
Puts you back into ketosis quickly
You’ve probably heard of the term “speed keto,” a technique that’s supposed to induce ketosis in a short period. Doing OMAD can help you enter ketosis within a 24-hour period, instead of the usual 72 hours or even longer for some people. 
Combining a form of fasting like OMAD and keto can be particularly useful if you’re trying to get back on track after a cheat day or high-carb refeed day (as part of a cyclical keto approach).
Weight loss due to a calorie deficit
While not all calories are equal—because some foods are low-quality sources of calories—you’re still likely to gain weight being in a calorie surplus all the time. This is why intermittent fasting strategies, such as OMAD, favor weight loss. It’s difficult to consume more than your daily calorie needs in one sitting, which can help lower the number of calories you typically consume per day.
A recent study also showed that consuming one meal per day instead of three meals in healthy subjects resulted in reduced fat mass and increased fatty acid oxidation during exercise. What’s interesting is that these subjects’ strength and aerobic capacity weren’t negatively affected. 
Improves blood sugar control and cholesterol
With over 130 million adults in the US living with diabetes or prediabetes, lifestyle changes have become more important.  If you’re using keto to bring your blood sugar to normal levels and reduce the need for medication, you might want to consider OMAD down the road. But, of course, speak with your healthcare provider first.
A systematic review and meta analysis also found that intermittent fasting and energy-restricted diets improve total cholesterol and triglyceride levels. 
Potential Drawbacks of OMAD