What is the OMAD Diet Plan?

OMAD stands for “one meal a day” and means just that: you only eat one meal per day. It is similar to intermittent fasting in that you only consume your calories in a relatively short period of time, typically between 1-2 hours of the day. It is considered to be an extreme fasting diet.

Since you’re only eating once per day, you typically consume far fewer calories than you otherwise would if you ate all day long. That is, for most people, it’s very hard to over-consume your daily caloric intake in one short sitting.

How Do You Implement the OMAD Diet Plan?

Starting the OMAD diet plan is relatively simple. First, choose a window of time in which you’ll consume your meal. Often, it’s easier for people to pick either lunch or dinner so time slots of 12 PM or 6 PM tend to work best for working people. Next, try to plan what you’re going to eat each day beforehand so you don’t just resort to ordering a large pizza and chicken wings (although technically you could on the OMAD diet). Consume your calories in that chosen window of time, then rinse and repeat the next day, and the next day, etc.

Note that you can still have calorie-free beverages during the off-hours like black coffee, diet soda, and unsweet tea. Make sure you’re drinking plenty of water and, as always, consult with your doctor before starting any new diet plan.

What Can and Can’t You Eat on the OMAD Diet Plan?

Technically, you’re able to eat whatever you want in that one hour time frame on the OMAD diet. “Although you’re technically allowed to eat whatever you want during this one meal, you’re still eating way fewer calories (which are units of energy) than you would typically need in a day” (Stieg, 2019). It should also be noted that if you opt to eat a salad and some soup rather than an entire apple pie, you’re likely to lose more weight more quickly and be healthier overall.

Pros of the OMAD Diet

• Eat What You Want: The good news about only eating one meal per day is that you’re allowed to eat whatever you want. As stated before however, it makes much more sense health-wise to try to consume a balanced diet in that window instead of a tub of ice cream.
• Simple: There’s no calorie counting, food tracking, data inputting, or anything else like that. “You don’t really need to consider your calories or worry about the exact nutritional profile of the food you eat, as long as you’re saving all of your calories for that one period of time, says New York City–based nutritionist Natalie Rizzo, RD” (Baum, 2019).

Cons of the OMAD Diet

• Extremely Restrictive: Obviously, if you’re only able to eat food in a small window of time per day, this can be highly restrictive and unappealing for many people.
• Hard to Get Nutritional Needs: If you’re only eating one meal per day, it’s sometimes unappetizing to eat that salad, fruit cup, sandwich, and side vegetables all in one sitting. While this is good to help reduce your caloric intake, it might mean that you’re not consuming enough of certain vital nutrients simply because you can’t consume that much food in one sitting.

Books on the OMAD Diet Plan

• Delay, Don’t Deny: Living an Intermittent Fasting Lifestyle (Gin Stephens & Dr. Kenneth Power): “Tired of counting calories, eliminating foods from your diet, or obsessing about food all day? If so, an intermittent fasting lifestyle might be for you! In this book, you will learn the science behind intermittent fasting, and also understand how to adjust the various intermittent fasting plans to work for your unique lifestyle.”
• The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting (Dr. Jason Fung & Jimmy Moore): “Fasting is not about starving oneself. When done right, it’s an incredibly effective therapeutic approach that produces amazing results regardless of diet plan. In fact, Toronto-based nephrologist Dr. Jason Fung has used a variety of fasting protocols with more than 1,000 patients, with fantastic success. In The Complete Guide to Fasting, he has teamed up with international bestselling author and veteran health podcaster Jimmy Moore to explain what fasting is really about, why it’s so important, and how to fast in a way that improves health.”
• The Obesity Code: Unlocking the Secrets of Weight Loss (Dr. Jason Fung): “Everything you believe about how to lose weight is wrong. Weight gain and obesity are driven by hormones—in everyone—and only by understanding the effects of insulin and insulin resistance can we achieve lasting weight loss.”
  

Evidence-Based Studies on the OMAD Diet

There are no studies specifically on the OMAD diet but there are a number of studies on fasting and extended fasting.

• Numerous Health Benefits: “A post hoc analysis of subjects from both [fasting-mimicking diet] arms showed that body mass index, blood pressure, fasting glucose, IGF-1, triglycerides, total and low-density lipoprotein cholesterol, and C-reactive protein were more beneficially affected in participants at risk for disease than in subjects who were not at risk” (Wei et al., 2017).
• Weight Loss: “[Alternative Day Fasting] appears to be an effective diet therapy for individuals with NAFLD that can achieve weight loss and improvement of dyslipidaemia within a relatively short period of time (4 to 12 weeks)” (Cai et al., 2019).
• Fasting and Cancer: “Fasting or fasting-mimicking diets (FMDs) lead to wide alterations in growth factors and in metabolite levels, generating environments that can reduce the capability of cancer cells to adapt and survive and thus improving the effects of cancer therapies” (Nencioni et al., 2018).