Last week we looked at Intermittent Fasting, but more specifically, Time-Restricted Eating. This week I wanted to discuss another form of Intermittent Fasting that has become very popular. 

OMAD.

One Meal a Day, or OMAD, has become very popular in fitness circles and has been adopted by many as a way to lose weight and improve their health. OMAD is an extreme version of Time-Restricted Eating, but instead of having a 6 to 10-hour eating window and 14 to 18-hour fasting window, one consumes their single meal in about an hour and fasts for 23 hours.

What are some of the proposed benefits of OMAD?

• Weight Loss due to Controlling Appetite and Calorie Intake
• Possible Maintenance of Fat-Free Mass
• Improved Health Parameters

To begin, we can look at weight loss. In 2007 a Randomized Control Trial was done by Stote et al., which compared eating three meals a day with one meal a day. The OMAD group experienced slightly more reductions in fat mass; however, they also experienced a significant increase in hunger. 

As I have discussed before, to experience weight loss (fat loss), one needs to be in a caloric deficit. Consuming all your calories within one hour can be very challenging, so it makes sense that the OMAD group had an easier time eating at a caloric deficit than the three meal a day group. Interestingly, the OMAD group consumed just ~65 kcal less per day than the other group. I believe it is worth mentioning that the OMAD group consumed high kcal foods to reduce the volume of food, meaning they were most likely consuming processed food. Is it possible that OMAD consisting of whole food ingredients would offer more benefits? Maybe. 

In the present study and additional studies, OMAD does not seem to be less effective at preserving fat-free mass (muscle mass). While a good thing, it does appear the methods used to assess fat-free mass were poor, and muscle mass was not directly measured. 

Lastly, there does not appear to be improvements in health parameters with subjects in the OMAD group. Those in the OMAD group experienced an increase in blood pressure (systolic and diastolic) along with an increase in LDL (bad) cholesterol and HDL (good) cholesterol. As I previously stated, the lack of health parameter improvements could have been influenced by the quality of the diet, but the food was the same between groups.

To close, OMAD can be utilized as a way to reduce caloric intake, but this is an extreme version of time-restricted eating. In addition to adherence, I have concerns with people consuming enough total protein with one meal. As I have mentioned before, there are benefits, especially for older adults, to spacing out protein intake throughout the day. This has to do with preserving and building muscle mass, which becomes harder as we age. 

Have you thought about adopting OMAD? Whether it is OMAD or another eating pattern, I believe it helps to ask yourself what your goals are and evaluate whether [insert eating pattern/diet here] is something you can sustain for the rest of your life. We want long-lasting change, not quick fixes.

I hope you found this information interesting. If you have questions or suggestions for topics you would like me to cover please do not hesitate to reach out!

That’s all for now!