Why Breakfast Can Support Muscle and Metabolic Health

Thomas DeLauer: All right, Dr. Rhonda Patrick. Everyone changes their mind or changes their perspective on things. What are a few things in fitness or nutrition that you have changed your mind about in the last five to seven years?

Dr. Rhonda Patrick: I have changed my mind about a few things as new data have emerged. That is what any scientist does. You reassess the evidence and reach new conclusions. My position has also shifted along a spectrum on some topics.

One of the biggest changes has been my stance on skipping meals, especially breakfast. Meal skipping has somehow become synonymous with intermittent fasting, but they are not the same thing. There are different forms of intermittent fasting, all of which involve a period without food. Many people who say they practice intermittent fasting are specifically skipping breakfast. I used to skip breakfast often myself.

As new data emerged and I spoke with muscle-protein-synthesis experts such as Stu Phillips and Brad Schoenfeld, I became concerned about missing protein after an overnight fast. We store glucose as glycogen and fat as triglycerides in adipose tissue, but we do not maintain a comparable free amino acid store. Without a continuing supply of amino acids, muscle breakdown can increase.

Muscle maintenance reflects the balance between muscle protein synthesis and breakdown. Two important signals stimulate muscle protein synthesis. One is protein intake, particularly essential amino acids such as leucine. The other is mechanical stress from resistance training. Breakfast can provide protein after an overnight fast, when you may otherwise become more catabolic. Resistance training can help offset that by providing the mechanical signal.

Skipping a meal also removes an entire opportunity to consume protein. You then have to make up that protein in the remaining meals. I was not doing that, even though I thought I was getting enough protein. That was another area in which I changed my mind.

Some studies have found a small amount of muscle atrophy with intermittent fasting among people who were not resistance training. Other studies, including one in women, combined intermittent fasting with resistance training and blunted some of that effect. Participants could still skip a meal without losing as much muscle.

That does not mean I oppose time-restricted eating. Time-restricted eating means consuming all your food within a defined window and then having a period when you are not eating or digesting. I still think substantial evidence supports eating within a daily window for metabolic health.

We are more insulin-sensitive earlier in the day. As the day progresses and melatonin production approaches, insulin sensitivity decreases. Studies that give people the same calories, macronutrients, and meals at different times find better glucose and insulin responses earlier in the day than in the evening. That is one reason not to eat a meal at 10 p.m.

You also need time away from digestion. I initially said “time to digest,” but I meant time to repair. During digestion, your organs are working rather than being fully in a repair state. A fasting period, much of which occurs during sleep, permits processes such as DNA repair and autophagy.

Time-restricted eating can therefore still be beneficial. The mistake is assuming that it must involve skipping a meal and losing the protein that meal would have provided. A better approach can preserve the same number of meals within a smaller window. Meal timing also matters for sleep. If your last bite is at 6 or 7 in the evening, digestion can continue for several hours, so the fasting period does not effectively begin at the moment of that last bite.

Thomas DeLauer: That is one of the biggest changes for me too. I no longer skip breakfast. Intermittent fasting helped me lose a lot of weight, but my view changed as I became leaner. If I fast frequently, I have less stored energy to draw from.

I might use early time-restricted feeding two days a week. It is not extreme. If I fast, I may skip dinner rather than breakfast. I now consider breakfast one of the more important meals because it literally breaks the fast. “Breakfast like a king, lunch like a prince, and dinner like a pauper” has generally been my philosophy.

Fasting is now an occasional practice rather than the rule. I might choose a 17-hour fast on a suitable day, but I would not do it every day. Skipping meals also reduces calorie intake. It removes an entire meal, which can make caloric restriction easier to implement than counting every calorie. People with overweight or obesity can benefit substantially from caloric restriction, and having more fat mass can reduce the proportion of weight lost from muscle.

Dr. Rhonda Patrick: When people decide simply not to eat, they are creating caloric restriction by another method. It can be an effective way to lose weight. The concern increases when someone is leaner, such as a mother trying to lose an additional 10 to 20 pounds. Brad Schoenfeld pointed me to a study suggesting that up to 30% of weight loss can come from muscle when people do not perform resistance training. They may be skipping meals, consuming too little protein, and missing one of the two important muscle-building signals.

Thomas DeLauer: Yeah.

Dr. Rhonda Patrick: Without resistance training, they also miss the mechanical signal. If protein intake is inadequate and the muscles receive no training stimulus, the body can draw amino acids from muscle. Muscle is technically an amino acid reserve, but you do not want to use it that way.

Thomas DeLauer: No, it is a last resort. Exactly.

Dr. Rhonda Patrick: It is a survival mechanism. Meal skipping can be an effective weight-loss strategy when it is used appropriately. People with overweight or obesity have more stored energy to work with than normal-weight people who are interested primarily in longevity. A normal-weight person does not need to skip breakfast every day to practice time-restricted eating.

Early time-restricted eating or feeding, abbreviated eTRE or eTRF, can preserve the same number of meals within a smaller window instead of spreading them across the entire day. That approach still provides a fasting period for repair.

Thomas DeLauer: My general rule is approximately 12 hours eating and 12 hours fasting. I naturally avoid food from about 7 in the evening to 7 in the morning, which is easy for me to do almost every day. I usually train fasted because I feel better that way. My post-workout meal then becomes breakfast.