How to Lose Fat & Gain Muscle With Nutrition | Alan Aragon

The episode is framed around Alan Aragon, introduced as a figure in fitness and nutrition known for a "strict reliance on evidence-based information" and for co-authoring widely cited studies and reviews. The planned scope is broad: seed oils, fasted training for fat burning, low-calorie and artificial sweeteners, sugar, alcohol, collagen, how to determine actual protein needs, meal timing, protein and carbohydrate intake relative to training, how women's hormone cycles affect training and nutrition needs, and eating and training for body composition change.

The stated motivation is the volume of advice both online and in the peer-reviewed literature, which makes it hard to know what matters for fitness and body composition goals. The introduction positions the guest as someone grounded in peer-review data but also willing to acknowledge individual differences and preferences. The portion of the interview covered here concentrates on protein dosing, the post-exercise "anabolic window," and fasted training.

The discussion opens with a familiar claim: that the body can only assimilate 30 grams of protein per meal. The question is posed in practical terms. What counts as a meal? If someone eats 30 grams and then another 30 grams an hour later, is that two meals, and can more than 30 grams ever be used?

The first answer is that the question itself contains a key variable. An isolated, quickly digesting protein behaves differently from a slower-digesting one, and either behaves differently again inside a mixed meal containing carbohydrate, fat and fiber. All of those conditions alter what happens physiologically.

The ceiling, it is argued, comes from blending two separate concepts. One is whole-body digestion and utilization, where protein has various metabolic fates serving different systems and homeostatic needs. The other is the specific muscle anabolic response, or muscle protein synthesis (MPS). The 25-to-30-gram cutoff (some say 20) refers specifically to MPS, where a plateau appeared at roughly 25 to 30 grams. That view held from the late 1990s and early 2000s until around 2016.

The study described as the turning point is a 2016 experiment by McNaughton and colleagues comparing 20 versus 40 grams of protein. Earlier research had used low-volume training, around 8 to 12 total sets of a couple of leg exercises such as leg extensions and leg presses. McNaughton's group instead used a roughly 24-set full-body regimen, described as more "ecologically valid" because it better mirrored real-world training by people trying to build muscle. Under those conditions, 40 grams produced a greater MPS response than 20 grams. A series of later studies is said to have further challenged the idea that MPS plateaus at 20 to 25 grams.

A more recent study pushed the dose up to 100 grams. Jorn Trommelen and colleagues compared 25 grams with 100 grams after exercise using milk protein, which is 80% casein (slow digesting) and 20% whey (fast). The 100-gram dose produced significantly greater MPS than the 25-gram dose. The study is criticized for lacking an intermediate dose, such as 40 or 50 grams, that would show whether MPS plateaus earlier. That matters because a lot of other research places the plateau somewhere between 30 and 50 grams.

Asked for an across-the-board post-resistance-training recommendation, covering whether the figure is 20, 30, 50 or 100 grams, whether it should scale with body weight, and how soon after training it should be eaten, the answer focuses on maximizing MPS generally. MPS is said to be larger when protein is dosed after exercise than at rest or when fasting, but doses beyond roughly 50 grams have not really been seen to maximize MPS further; the range cited is about 30 to 50 grams.

A paper co-written with colleague Brad Schoenfeld, asking what the maximal anabolic dose of protein per meal is for muscle building, reduced the literature to roughly 0.4 to 0.6 grams per kilogram of body weight, or 0.2 to 0.25 grams per pound. A misheard figure of "0.2 to 0.5" is corrected in the conversation to "0.2 to 0.25." Put simply, the target is grams of protein equal to about a quarter of body weight in pounds, and it is confirmed as a per-meal figure.

The follow-up question separates two scenarios: a meal eaten within about two hours after resistance training, and a meal on a non-training day. The answer is that this is "so weird" and "complicated," and explaining it requires going back about 20 years.

The history starts with John Ivy and Robert Portman's book 'Nutrient Timing' from around 2003 to 2004. It promoted a narrow post-exercise "window of opportunity": eating a fast-digesting protein together with a highly glycemic, highly insulinemic carbohydrate within 30 to 60 minutes after exercise to maximize the anabolic response, recovery and muscle gain. The critique is that this hypothesis rested on subjects who trained after an overnight fast. A regular medium-sized mixed meal is said to have an anabolic/anticatabolic effect lasting three to six hours, depending on its size.

The argument continues that people whose top priority is gaining muscle as fast as possible almost never train fasted. They typically eat at least a couple of hours beforehand, so nutrients are still circulating during the session. Someone who eats an hour before training may still be absorbing that meal afterward. On that basis, the post-exercise window is described as lacking external validity for real-world conditions. A 2013 narrative review criticizing the window is said to have angered researchers who did the seminal work in the area.

A meta-analysis followed, described for listeners as "a study of the studies" that pools effect sizes to see where the evidence leans. It included studies where protein was timed within an hour before or after exercise, compared with control conditions involving at least two hours of nutrient neglect on both sides of the training bout. Statistician James Krieger ran the regression analysis. The finding: as long as total daily protein was about 1.66 to 1.7 grams per kilogram (about 0.7 grams per pound) or more, timing relative to training did not make a difference.

The practical takeaway drawn in the conversation is that there is no need to obsess over the post-training window, especially if you eat before training. The case of someone who last eats at 8:00 PM, wakes at 7:00 AM and trains at 10:00 AM is offered as a situation where prioritizing protein and other nutrients after the session might make sense. A rule of thumb is offered: if you are still burping your pre-exercise meal near the end of the workout, there is no need to rush. The host notes that he prefers to take in nothing before training except caffeine, electrolytes and water.

The reason the answer is "weird and complex" is the time course of a single resistance training bout. MPS peaks 24 hours after the session and can take 48 to 72 hours to return to baseline. That reframes the window entirely:

So, the anabolic window is actually not hours, but days.

This leads to a hierarchy of importance. Total daily protein comes first. If that is right, the timing of the individual doses that make up the total is "just a distant secondary concern."

The host tests the principle with a lopsided day: some caffeine, a scoop of whey and a few almonds before a one-hour morning session, then chicken breast, salad and a slice of bread at 3:00 PM, then a large dinner of two rib-eye steaks (an admitted exaggeration) providing perhaps 75 to 100 grams of protein. Can all of that be used for MPS? The short answer given is yes, with nuance to come from the studies.

The question is then broadened to whether an occasional very high-protein meal is a problem, especially when protein is low earlier in the day. The practical reasoning: many people struggle to spread protein evenly or to get enough at morning and midday meals, and in the United States dinner tends to be the largest meal, often with high-protein restaurant options like steak, chicken breast or fish. Assuming calories are appropriate, is back-loading protein bad for body composition or health? The answer is "no," with the caveat that it depends on the population, for example competitive bodybuilders. The host specifies the general population: men and women from teens to 75 doing resistance training and some cardiovascular training, not physique competitors or marathon and ultra runners.

Two trials are offered as support. In a 2014 study, the research group compared 25 grams of whey taken immediately before exercise with 25 grams taken immediately after, over about 10 weeks (described as "8 or 10, probably 10"). The logic was that if a post-exercise window exists, what matters is when nutrients are available in circulation, which typically peaks one to two hours after ingestion, rather than when they are eaten. Taking protein before training would have it peaking in the blood around an hour later, inside the window. Neither condition showed a significant advantage.

Around 2023 to 2024, colleague Yassin Lak ran a randomized controlled trial that exaggerated the contrast. One group had 25 grams of protein immediately before and after resistance training. The other neglected all nutrients for three hours on both sides of the session. Total daily protein was optimized near a gram per pound, about two grams per kilogram. At the end of the study, described as 10 or 12 weeks long, there was no significant or meaningful difference in muscle size or strength gains.

The host describes this as reassuring for busy schedules, where a shower and a meeting or dinner may follow training with no chance to eat in the "anabolic window." His summary, which the guest broadly affirms: timing is very flexible, total intake appears to center around 0.7 to 1 gram per pound of body weight per day, and per-meal amounts somewhat above or below 20 to 30 grams are likely fine. He also highlights the distinction between when protein is eaten and when amino acids actually reach circulation, a couple of hours later.

total daily protein is the cake. The specific timing of protein relative to the training bout, that is the icing on the cake, and it's a very thin layer of icing on the cake.

The conversation then turns to fasted training, broadened to include cardiovascular work (long slow distance or high-intensity intervals, anything that raises heart rate deliberately for 12 minutes or more) along with resistance and circuit training. "Fasted" is defined as four hours without food during the day, or 8 to 12 hours including overnight sleep. The host asks for a distinction between burning stored body fat and burning circulating dietary fat.