Waffle House is now selling a 53g Protein Bowl. Raising Cane's is pushing meals with 80+ grams of protein. McDonald's, Wendy's, Arby's, and Taco Bell have all reshuffled menus around grams of protein. Journalist Michael Easter, writing in his Two Percent newsletter, flagged the obvious pattern: when fast-food chains adopt a diet trend, the hype has already outrun the evidence. He saw it with low-fat, low-carb, and keto. So the question for serious endurance athletes is straightforward — is proteinmaxxing a real performance lever, or is this the next thing you'll be embarrassed to admit you tried? The short answer: the protein range that helps you is well below what the maximalists are pushing, and exceeding it costs you carbs you can't afford to lose.
What "Proteinmaxxing" Actually Means
Proteinmaxxing is internet shorthand — borrowed from the looksmaxxing subculture — for aggressively maximising daily protein intake. The version that went mainstream in 2025 isn't a specific diet. It is a cultural shift: protein has displaced fibre, omega-3s, and "balanced macros" as the nutrient people optimise around. Targets vary, but the maximalist end pushes 1g per pound of bodyweight or more (≈ 2.2g/kg) — sometimes a lot more in muscle-building and GLP-1 contexts.
For an 80kg endurance athlete, that maximalist target lands at roughly 180g of protein per day. That is double the standard RDA (0.8g/kg) and well above the 1.2–1.6g/kg most sports nutrition textbooks recommend for endurance training. Whether the extra 50g is doing anything useful — or quietly costing you elsewhere — is the actual question.
What the Evidence Actually Says
Three claims drive the proteinmaxxing narrative for athletes. Each has a kernel of truth that gets stretched past the data:
- More protein builds more muscle. Partially true, with a hard ceiling. Morton et al.'s 2018 meta-analysis (43 studies, 1,863 participants) put the point of diminishing returns at 1.62g/kg/day for trained individuals doing resistance work. Beyond that, additional protein adds no extra lean mass. Specific contexts (energy deficit, masters athletes, GLP-1 use) may shift the curve to 2.2g/kg. Above that, you are gilding the lily.
- More protein burns more fat. Real but modest. Protein has a higher thermic effect (~25%) than carbs (~8%) or fat (~3%), and it is more satiating per calorie. The practical effect: athletes in a fat-loss phase find adherence easier on a higher-protein diet — not because protein is magic, but because they stay full and accidentally eat less.
- More protein protects you on GLP-1. This one is genuinely supported. Clinical trials show 20–40% of weight lost on semaglutide is lean mass. Resistance work plus 1.6–2.2g/kg/day appears to shift that ratio favourably. The GLP-1 for athletes guide covers the protocol in depth.
What the ISSN 2017 position stand and a decade of follow-up research do not support: that protein is the dominant performance nutrient for endurance work. There is also a quietly important second-order claim emerging from the mitochondrial-biogenesis literature — protein contributes to building the enzymes that make trained mitochondria efficient — but those adaptations are still primarily driven by training stimulus and carbohydrate availability, not by the third scoop of whey. For a triathlete, marathoner, or cyclist, carbs still win races. Protein is structural. Carbs are fuel.
The Cost of Crowding Out Carbs
Here is where proteinmaxxing gets dangerous for endurance athletes specifically. Total caloric intake on a training day is finite — bounded by appetite, schedule, and gut tolerance. Every 100g of protein you eat (400 kcal) is 100g of carbohydrate you didn't.
An athlete training 12 hours a week who follows a generic 2.2g/kg target ends up under-fuelling. Glycogen stores don't replenish between sessions. Heart rate drift on long efforts gets worse. Threshold work feels harder than it should. The athlete blames overtraining when the actual problem is a protein-heavy diet displacing the carbs that drive aerobic adaptation — and the training load stays stuck because the system never recovers.
The carbs-per-hour reference shows what gut-trained endurance athletes target during sessions — 60–90g/hour for most, up to 120g/hour at the elite end, often using the 1:0.8 glucose-fructose ratio to unlock the upper bound. Hitting those numbers during effort while also stuffing 180g of protein into the day means total carb intake has to be substantial. Most age-groupers don't have the appetite or schedule for both.
A Practical Framework for Endurance Athletes
Forget the round numbers from social media. The sports-nutrition literature — ISSN position stand, Morton meta-analysis, the protein-distribution work from McMaster and Stirling — converges on this for athletes training 8–15 hours a week:
- Daily target: 1.6–2.0g/kg/day. For an 80kg athlete, that is 128–160g — already the high end of normal eating, well below maximalism. Run your number through the TDEE & macro planner to see what that looks like alongside your carb and fat targets.
- Distribution: 4–5 feedings of 0.3–0.4g/kg, each containing at least 2.5–3g of leucine — the amino acid that triggers muscle-protein synthesis (MPS). For most adults that means roughly 25–40g of high-quality protein per meal. The MPS response saturates in that window; eating 80g in one shot doesn't double the result.
- Timing — and the anabolic window myth: The "30-minute anabolic window" was largely overturned by Schoenfeld's 2013 meta-analysis. What still holds: a 20–40g dose within 1–2 hours after key sessions. Casein-style slow protein before bed has decent support for overnight recovery (Snijders 2015), particularly in resistance-training blocks.
- Source quality: Whole-food protein (eggs, dairy, fish, lean meat, legumes) brings micronutrients, fibre, and fats that protein-isolate bars and fast-food bowls strip out. Use shakes to fill gaps, not as primary sources.
- Plant-based athletes: Leucine content per gram is lower in most plant sources, so target the upper end of the daily range (1.8–2.2g/kg) and pair complementary sources at each meal (lentils + rice, tofu + quinoa, hemp + oats). Soy isolate and pea protein both clear the leucine threshold per 30–40g dose; rice protein on its own typically doesn't.
A workable day for an 80kg athlete at 1.8g/kg (144g total): 30g at breakfast (Greek yoghurt + oats), 35g post-key session (whey + banana), 40g at dinner (salmon + lentils + veg), 25g pre-bed (cottage cheese or casein). Four feedings, all above the leucine threshold, no protein gimmicks required.
If you are not sure where your current intake sits, log three typical days. Most endurance athletes are surprised at how easily they clear 1.6g/kg without trying — and how unnecessary the extra 50g per day actually is.
When Proteinmaxxing Makes Sense (And When It Doesn't)
There are contexts where pushing toward 2.0–2.2g/kg is genuinely defensible:
- Active fat-loss phase with a meaningful caloric deficit (>500 kcal/day). Higher protein preserves lean mass and helps satiety.
- GLP-1 use while training. Muscle-loss risk is real; resistance work plus high protein is the standard mitigation.
- Masters athletes (50+) facing anabolic resistance. The leucine dose required to trigger MPS climbs with age — the 25g that works at 30 may need to be 35–40g at 60.
- Concurrent resistance training aimed at building, not just maintaining, lean mass — including the off-season strength blocks that go into a serious Ironman plan.
Contexts where proteinmaxxing is actively counterproductive: peak training blocks, race week, ultra-distance prep, anyone struggling to recover between key sessions. In those phases, every extra gram of protein is a gram of carbohydrate you didn't eat — and your race depends on the carbs.
The Fast-Food Protein Bowl Test
Easter's point about Waffle House is worth taking seriously. The 53g Protein Bowl exists because protein-forward marketing sells, not because the food is engineered for performance. The same bowl typically delivers high saturated fat, low fibre, low micronutrient density, and a sodium load that — as the sodium reference shows — would qualify as a meaningful chunk of a hot-weather race-day ration in one sitting.
A useful test before adding any "protein" product to your routine: would this still be on your plate if you ignored the protein number? If yes — eggs, Greek yoghurt, a real chicken bowl with vegetables, cottage cheese — you are eating food. If no, you are eating a protein delivery vehicle marketed by a chain whose business depends on the trend continuing. Use the macro-periodization calculator to plan macros around the actual demands of your training week instead — protein scales with your training stress, not with whatever the menu board is shouting about today.
Proteinmaxxing isn't wrong. It's over-applied. For endurance athletes, the useful version is "hit 1.6–2.0g/kg, distribute across 4–5 meals that each clear the leucine threshold, prioritise whole-food sources, and scale carbs to your training load." The maximalist version pushed by fast-food menus and looksmaxxing forums is engineered for engagement, not race performance. If you are losing weight, on a GLP-1, or building muscle alongside endurance work, push toward the upper end. If you are in a hard training block, prioritise carbs and let protein sit at the lower end. The discipline that wins races is matching the macro to the moment — not maxing one number while the others quietly fall apart.