Andy Galpin's Nutrition and Hydration Fundamentals

Ask ten nutrition coaches for the single correct diet and you will get ten different answers, delivered with the same certainty. Human performance scientist Andy Galpin, who hosts the podcast Perform, thinks this is a trick of framing. Zoom out far enough, he says, and the ten answers turn out to share the same skeleton. Different diets are just different costumes on the same body.

Galpin calls this shared skeleton "the 90%." It is his answer to the most common question he gets: just tell me the basics. Rather than picking a side in the keto-versus-Mediterranean-versus-intermittent-fasting debate, he lists the ten to fifteen things that every evidence-based eating style is quietly doing, no matter what it calls itself.

"The 90%, to me, is a way of saying, look, if you were to examine every nutrition program, every theme, every diet, every eating style, you'll start to realize there's a bunch of common themes." — Andy Galpin [03:50]

The list starts predictably: eat mostly single-ingredient, minimally processed food, and manage caloric balance, whether through counting, time-restricted eating, or cutting a food group (05:41, 08:48). It gets more specific from there. Galpin's rough rule for fiber is 13 to 15 grams for every 1,000 calories eaten, so a 2,000-calorie diet should carry roughly 25 to 30 grams (11:48). Non-starchy vegetables, the greens and colors rather than the potatoes and rice, should fill about half the physical volume of a plate (12:18). And protein deserves special attention not because it is more important than fat or carbohydrate, but because it is the macronutrient people accidentally skip.

One detail resists the tidy narrative that whole food is always better raw. Cooking spinach denatures it, which makes its iron easier to absorb, while cooking, blending, or chopping any vegetable exposes it to oxygen and burns off some antioxidants (15:10, 15:34). Galpin's answer is not a verdict but a shrug: use a mix of raw and cooked, because each method trades one nutrient for another.

The arithmetic of muscle

The most counterintuitive number in the episode is not about food quality at all. It is about the cost of tissue. Most people, if asked to guess, know that losing a pound of fat takes roughly 3,500 calories of deficit (49:29). Almost nobody knows the inverse: building a pound of new muscle costs only about 1,800 calories, a figure Galpin credits to sports scientist Eric Helms and researcher Ben House (51:07).

The gap between those numbers explains something bigger. A pound of stored body fat holds about 4,000 calories of usable energy. A pound of muscle holds only about 800, roughly a fifth as much (51:36). Fat is a cheap, efficient battery. Muscle is an expensive, high-maintenance factory that burns through protein and ATP daily just to stay in business, and gives almost nothing back if you break it down. That mismatch, Galpin argues, is exactly why muscle is hard to build and easy to lose, while fat is the reverse.

"Muscle is not a storage depot for calories, but fat truly is." — Andy Galpin [51:36]

This is also why protein needs shift depending on the goal. Galpin's baseline for muscle growth is 1.6 grams of protein per kilogram of body weight, a threshold beyond which extra protein stops adding much extra growth (53:02). He personally coaches people toward roughly 2.2 grams per kilogram, the equivalent of one gram per pound, not because the data demand it but because it helps with satiety and recovery, a distinction he frames as the difference between what the evidence "is" and what he thinks someone "ought" to do (53:56). In a caloric deficit, though, the number climbs again: protecting muscle while eating less may require closer to 3 grams per kilogram (55:58).

None of that protein matters as much as one other variable. Citing exercise physiologist Stu Phillips, Galpin is blunt that strength training, not protein intake, is the largest single driver of muscle growth, in surplus or deficit (58:13). Calories come second. Protein is the tiebreaker that matters most once someone is already lean and already training hard.

Fueling during exercise follows a similar logic of diminishing returns. Most casual exercisers, doing 30 to 45 minutes of moderate work, do not need to eat carbohydrate during a session, because there is usually enough glucose already circulating (24:38). But elite endurance athletes chasing a finish line have pushed intra-workout carbohydrate intake to 80 grams an hour, with some reportedly near 120 grams (35:42). Galpin's caveat is practical rather than physiological: that much sugar and fluid sloshing in the stomach can cause real gastrointestinal distress, so the gut has to be trained gradually, the same way a muscle would be (36:05, 37:03).

There is a second, less obvious reason carbohydrate matters for muscle. Glucose is not just fuel for the workout. Galpin describes muscle as a "donor of carbon," meaning some of the sugar eaten gets stripped of its water molecules and its carbon is stored directly inside muscle tissue as building material, not just burned for energy (25:53, 28:00). That is part of why more muscle mass improves blood sugar regulation over time: bigger muscles act as a bigger sink for glucose. Timing, however, barely matters. Research from Galpin's own lab and others suggests that as long as total protein intake over 24 hours is adequate, it does not matter whether it arrives before or after a workout (30:07).

A formula for water, and a philosophy for coaching

Hydration gets the same treatment: strip away the mysticism, replace it with a formula. Galpin's baseline, a daily habit rather than a workout rule, is to drink about half of body weight in ounces of water per day, so a 200-pound person aims for roughly 100 ounces (32:10). During exercise, the rule his colleague, Stanford neuroscientist Andrew Huberman, nicknamed the "Galpin Equation" calls for 3 to 6 ounces of fluid every 15 to 20 minutes (32:37). After the workout, the target is to replace 125 to 150 percent of whatever body weight was lost in fluid, measured with a naked weigh-in before and after, because people left to their own devices tend to drink back only about half of what they sweated out (33:25, 34:25).

The most quietly radical part of the episode is not a number at all. It is Galpin's coaching sequence for changing someone's diet, which begins by adding, not subtracting.

"I will very rarely start someone's nutrition program by eliminating foods or restricting calories. Almost always it's the opposite." — Andy Galpin [40:01]

The method has three steps: first, find what is missing (a low mineral, a low fiber intake, insufficient protein) and add foods to fix it, before ever removing anything (40:01). Second, once quality intake is established, tinker with amounts and types, adjusting calories, protein, or the ratio of soluble to insoluble fiber (44:22). Third, fine-tune the details, like the exact timing of a pre-workout meal (45:05). The logic is psychological as much as physiological: crowding a plate with high-satiety, nutrient-dense food naturally displaces the junk, without the negative experience of having food taken away.

Galpin closes the episode on a claim that has nothing to do with macronutrients. He defines a high performer, athlete or not, as someone who is simply better at managing energy in all its forms: caloric, emotional, physical, cognitive.

"The people who are the highest performers are the best at energy management, and energy has a lot of different forms." — Andy Galpin [62:35]

It is a fitting close for an episode built entirely on the idea that expertise is not about finding one secret trick. It is about knowing which few things actually matter, and managing them consistently, whether that thing is a calorie, a gram of protein, an ounce of water, or an hour of attention.