Do You Need a Calorie Surplus to Build Muscle? | Dr. Eric Helms

Episode Overview

• Central Question: Host Dr. Jordan Feigenbaum (author of Signal) and guest Dr. Eric Helms (Director of SPRINZ at Auckland University of Technology, co-founder of MASS Research Review, Chief Science Officer and coach at 3D Muscle Journey, lead author of The Muscle and Strength Pyramid books, and co-host of the Iron Culture podcast) investigate whether a calorie surplus is actually required to build muscle, or if lifters can fund muscle growth using energy stored in their own body fat.
• Tissue Energetics and Muscle Math: The episode deconstructs the flawed heuristic of defining calorie maintenance by scale weight stability, breaks down the actual rate of dry protein accretion in humans, and reviews recent modeling by Nikolaidis et al. showing that building 1 kg of wet skeletal muscle requires only ~3,500 kcal in total.
• The Training Stimulus Ceiling: Before examining nutrition, Feigenbaum and Helms establish how mechanical loading dictates muscle mass ceilings across a continuous spectrum—from astronauts losing muscle in microgravity to untrained individuals growing from walking or 30-RIR squats, as well as the physiological realities of biological sex differences and exogenous testosterone.
• The Body Fat Constraint Model: Using Dr. John Speakman's Dual Intervention Point Model, Relative Energy Deficiency in Sport (RED-S), and meta-regressions on protein intake and calorie deficits, they demonstrate that current body fat percentage—rather than training age alone—determines whether endogenous fat stores can pay for hypertrophy or if the body will oxidize amino acids for fuel.
• Practical Application Across Populations: Through controlled studies (Rozenek, Garthe, Vargas-Molina) and real-world examples from drug-tested IPF powerlifting, natural bodybuilding, sumo wrestlers, and GLP-1 therapy patients, this conversation provides actionable calorie and protein frameworks tailored to specific body fat brackets.

Key Concepts

• True Energy Maintenance vs. Scale Weight Stability: Defining calorie maintenance as "body weight stability" is flawed. Fat mass is 100% pure lipid/triglyceride (while adipose tissue is 85% to 90% fat) and stores 5 to 6 times more energy per kilogram than lean mass (which is ~75% water and grouped by DEXA with glycogen and bone). If an individual gains 1 kg of lean mass and loses 1 kg of fat mass, their scale weight remains neutral, but they were retrospectively in a net energy deficit. True maintenance is the energy intake at which you do not rely in net on endogenous body stores to meet energy needs; a deficit relies in net on endogenous stores, and a surplus accumulates stores from exogenous intake.
• The Stimulus Predicts the Ceiling: The molecular machinery for muscle protein synthesis does not become dysfunctional as a lifter becomes more advanced; rather, a given training stimulus predicts its own ceiling via a curvilinear response. In typical 8- to 12-week university studies (~70% males), novices gain 1 to 3 kg of lean tissue (or 3 to 4 kg on intensive maximized protocols). Modeling data shows that if a lifter gains 3 kg in their first 8 weeks and never changes their training protocol, gains drop to 0.5 kg (one-sixth) between weeks 72 and 80.
• The Continuum of Mechanical Loading: There is no binary division between "trained" and "untrained"—everyone is adapted to their baseline daily loading. Astronauts in microgravity lose muscle despite using flywheels, bands, and electromagnetic devices, then regain it upon returning to Earth's gravity. Conversely, bedrest causes muscle loss, walking induces hypertrophy in sedentary individuals, and tying weights to the limbs of quails, chickens, and rabbits causes rapid hypertrophy followed by a new plateau without extra bulking calories. Similarly, sumo wrestlers and super-heavyweight powerlifters (like Ray Williams) carry massive fat-free mass because moving a heavy body daily acts like living in a 1.5G gravity environment. While lab ultrasound models over ~10 weeks show a minimum effective dose (MED) of at least 4 sets per muscle group per week close to failure, an untrained 70 kg person who can squat an empty 20 kg bar for 20 to 50+ reps would still experience quad hypertrophy doing 1 set of 5 reps (~30 RIR) three times a week for 12 weeks because it exceeds their daily baseline. Conversely, national-level weightlifters and powerlifters experience measurable lean mass losses during traditional periodization tapers when volume drops, even as 1RM strength peaks.
• Baselines, Biological Sex, and the "Second Puberty" Hypothesis: After puberty, men and women experience the same relative proportion of muscle gains from resistance training despite massive differences in circulating testosterone; men only gain more in absolute terms because they exit puberty with a higher baseline of muscle mass. Citing Bhasin et al.—where chemically castrated men gained lean mass across exogenous testosterone doses even without training—Helms theorizes that anabolic steroids do not directly amplify the mechanical training signal, but rather induce a "second puberty" that shifts the user's baseline muscle mass upward. (Helms hedges that the exact molecular mechanisms of this baseline shift, muscle memory, and ultimate growth limits like myonuclear domain control or vascular supply could be better understood in 5 years.)
• The True Energetic Cost of Muscle Growth: Gaining ~4 lbs (~2 kg) of wet muscle in 2 months equals ~32 g/day of wet tissue, which is only ~8 to 10 g/day of actual dry contractile protein. A preprint by Nikolaidis et al. modeled the cost of building 1 kg of wet skeletal muscle across five additive components: stored tissue energy, biochemical synthesis cost, physiological deposition cost, resting maintenance during accretion, and diet-induced thermogenesis (~10% of consumed energy). Validated against animal, drug, feedlot, and lab-grown meat models, the total cost is ~3,500 kcal per kilogram (variance: 3,200 to 3,700 kcal/kg). Gaining 1 kg of muscle in a month requires only ~115 kcal/day; gaining 1 kg over 3 months requires just ~40 kcal/day. An 80 kg male at 20% body fat carries over 100,000+ kcal of stored fat energy.
• Dual Intervention Points and Energy Availability Constraints: Once amino acids, triglycerides, or glucose enter the bloodstream, the muscle does not care whether the energy came from food or endogenous fat stores. However, Dr. John Speakman's Dual Intervention Point Model explains that the body defends both an upper and lower body fat limit, with an unregulated zone in between (Feigenbaum hedges that equating Speakman's lower point to the exact hypertrophy constraint threshold is speculative). When a lifter drops below their lower intervention point, the hypothalamus perceives an emergency and triggers Relative Energy Deficiency in Sport (RED-S). In 1960s/1970s total starvation studies, men with Class 2 or 3 obesity showed minimal changes in protein oxidation during days of fasting, whereas men with single-digit body fat experienced a 2- to 3-fold increase in leucine oxidation and gluconeogenesis as their bodies burned protein for fuel. Furthermore, Trexler's graduate research on post-contest natural bodybuilders showed that for ~10 weeks (2 to 3 months) after a show, a large calorie surplus resulted exclusively in fat gain (plus water/glycogen), demonstrating a lag period where the body prioritizes restoring minimum body fat before permitting muscle growth. (Conversely, Helms notes that clenbuterol acts as a recomposition agent by forcing fat mobilization at low body fat levels while acting anti-catabolically).
• Evidence from Controlled Bulking and Deficit Studies:
• Rozenek et al. (2002): Untrained university males lifting hard 4 days/week for 8 weeks consumed either their habitual diet, habitual diet + 2,000 kcal/day of pure maltodextrin, or habitual diet + 2,000 kcal/day of maltodextrin and protein. Both +2,000 kcal groups gained ~3 kg of lean mass with zero fat gain. The habitual group was in a slight net deficit (losing ~1 kg of fat and gaining ~1.5 kg of lean mass), showing that relying on endogenous stores constrained rapid novice growth by ~50%.
• Garthe et al. (2013): Elite Norwegian athletes lifting 4 days/week alongside sport conditioning ate either a dietitian-prescribed surplus (~600 kcal/day actual difference between groups) or a habitual/slight surplus intake. Both groups gained significant lean mass and 1RM strength with only a tiny, non-significant advantage for the +600 kcal group; however, the +600 kcal group gained almost exclusively body fat from the extra calories and suffered worse sprint times and jump heights.
• Ruffieux, Trexler, & Helms Meta-Regression: Analyzing protein intake in a deficit across male body fat tertiles (high: >20%, middle: 12%–20%, low: <12%; add 7–8% for women), protein above ~1.6 g/kg/day offered minimal extra benefit for those over 20% body fat (with ~1.9 g/kg/day preventing lean mass loss on average). In the leanest tertile (<12% body fat), the inflection point to prevent muscle loss shifted to ~2.5 g/kg/day with a flattened slope (diminished returns from protein alone).
• Murphy et al. Meta-Regression: Found an average inflection point of a 500 kcal/day deficit before lean mass is lost during resistance training, with recomposition very common in a 100 to 300 kcal/day deficit. (Helms caveats that this dataset had a massive distribution and mostly featured untrained, overweight/borderline Class 1 obese subjects doing low-dose training).
• Vargas-Molina et al.: Late-stage novice males (average body fat in the low 20s%) training to failure for 8 weeks were prescribed maintenance or a deficit. Back-calculated via DEXA, both were in net deficits (~150 kcal/day vs. ~350 kcal/day) due to common free-living tracking/label errors. Both groups gained ~1 kg of lean mass with no significant difference between them, while the ~350 kcal deficit group lost proportionately more fat (Helms notes there was no third surplus group for comparison).
• Intramuscular Fat and GLP-1 Weight Loss: In the "Semalean" study on semaglutide (GLP-1 therapy), non-exercising subjects lost 15+% of their body weight over a year. Over half had sarcopenic obesity at baseline (which decreased by study's end), and despite losing DEXA lean mass, their grip strength improved—likely from clearing intramuscular fat and carrying less dead weight.
• Evolutionary and Endocrine Adaptations to Low Energy Availability: Referencing Asker Jeukendrup and Areta's pushback on the 2023 RED-S consensus statement, Helms notes that hunter-gatherers and subsistence farmers live in chronic mild low energy availability at ~9% body fat, adapting via shorter stature (e.g., 5'5" vs. 5'10"). In women, extreme energy deficits (even in women with obesity on starvation diets) rapidly perturb luteinizing hormone (LH) pulsatility, an early driver of oligomenorrhea/amenorrhea, and very-low-calorie diets require at least 10 g/day of fat to prevent bile duct failure.

Quotes

• At 0:00:02 - "You have to be in a calorie surplus to build muscle. That's the rule. Well, at least it's been the rule for as long as I've been lifting." - Dr. Jordan Feigenbaum introducing the central dogma the episode deconstructs.
• At 0:00:32 - "So today, can you build muscle out of your own body fat? Not transform fat into muscle or muscle into fat, but can you use the energy stored in your own body to pay for the protein going into your quads?" - Dr. Jordan Feigenbaum framing the physiological mechanism of body recomposition.
• At 0:13:00 - "I think it's really important to note that if someone was to gain a kilogram of lean mass and lose a kilogram of fat mass, they would be at neutral body weight, but they would actually have been in a deficit retrospectively." - Dr. Eric Helms explaining why scale weight stability is a flawed definition of calorie maintenance due to the 5- to 6-fold higher energy density of fat tissue.
• At 0:13:47 - "Maintenance is actually the intake at which you are not relying in net on body stores to meet your energy needs." - Dr. Eric Helms providing the precise physiological definition of energy maintenance.
• At 0:24:41 - "Does the stimulus actually predict the ceiling? And I have landed more on that, because that also comports with the notion that a walking program is a hypertrophy program for some people, that bed rest results in a decrease in muscle mass." - Dr. Eric Helms explaining why muscle mass adapts to a continuous spectrum of daily mechanical loading rather than a binary trained/untrained state.
• At 0:27:01 - "Imagine an Earth where we had 1.5 times gravity. Everybody would be bigger, more muscular, and have more bone mineral density, right? And this means that there's really no such thing as being trained or untrained." - Dr. Eric Helms illustrating how baseline environmental loading dictates muscularity, which also explains the massive lean mass of sumo wrestlers and super-heavyweight powerlifters.
• At 0:33:51 - "I think a lot of what we see as the quote-unquote synergistic benefit of going on anabolic steroids with resistance training is actually seeing people gaining muscle from resistance training while essentially inducing a second puberty of whatever degree of the androgens you're taking." - Dr. Eric Helms explaining his theory that exogenous androgens shift baseline muscle mass rather than amplifying the mechanical transduction signal.
• At 0:36:28 - "Men and women usually exit puberty with different amounts of muscle mass, and because men typically have more muscle mass, they end up gaining more in an absolute sense, but the relative improvement between men and women, despite large differences in testosterone, is effectively the same." - Dr. Jordan Feigenbaum clarifying why circulating testosterone differences between sexes do not alter relative hypertrophy rates post-puberty.
• At 0:37:44 - "Half a pound a week is about 227 grams. So spread across seven days, you're looking at roughly 32 grams of wet muscle tissue a day, let's call it 30. And wet is an important word here because muscle is about three-quarters water. The actual dry protein you're laying down is closer to eight grams a day, give or take." - Dr. Jordan Feigenbaum breaking down the daily physical mass of actual contractile protein accrued during a productive muscle-building phase.
• At 0:43:23 - "And that overall number is about 3,500, but not per pound, per kilogram." - Dr. Eric Helms citing the Nikolaidis et al. preprint on the total energetic cost of building 1 kg of wet skeletal muscle tissue.
• At 0:54:46 - "The Nikolaidis paper suggests, well, look, you only need 115 calories a day to do that, right? And so through this model, this central organizing theory we're trying to work towards, that would mean your energy availability constraint then would be: do you have an excess of 115 calories from somewhere?" - Dr. Jordan Feigenbaum translating the 3,500 kcal/kg figure into daily energy requirements for a lifter gaining 1 kg of muscle per month.
• At 0:56:31 - "What if this person is more well-trained, they're closer to their ceiling, and now it's three months where they're gaining a kilo of muscle? Well, now it's like 40 calories a day, and you're like, well, who doesn't have 40 calories a day excess? And it's like, well, what if you're really lean?" - Dr. Jordan Feigenbaum showing how negligible the daily energy cost of hypertrophy is for advanced lifters, unless they are constrained by very low body fat.
• At 1:05:34 - "When we talk about the leanest tertile, people under 12%, now it wasn't 1.9 grams per kilogram that was the average intake where you didn't see losses of muscle mass, it was like 2.5, right?" - Dr. Eric Helms discussing the Ruffieux, Trexler, and Helms meta-regression on how protein needs increase in a deficit at low body fat levels.
• At 1:09:42 - "The leaner you are, the more the body is looking at that local constraint and going, I'm no longer interested in building this up, I want to tap into it as the emergency fund." - Dr. Eric Helms describing how the body shifts toward oxidizing amino acids and defending fat stores below the lower intervention point.
• At 1:14:24 - "Once amino acids, triglycerides, or glucose gets in the blood, where it came from or how it got there sort of doesn't matter. It's going to be then dependent upon where does it need to go." - Dr. Eric Helms explaining why endogenous fat stores can seamlessly pay the energetic cost of muscle protein synthesis when body fat is adequate.
• At 1:20:59 - "If you're a late-stage novice who has a 20% body fat as a male and you go on a pretty good training program, within a 100 to 400-ish calorie deficit, that's not going to be the constraint to how much muscle you can grow." - Dr. Eric Helms summarizing the practical takeaway from the Vargas-Molina et al. study.
• At 1:29:59 - "I don't need much energy to grow at this unfortunately slow rate that I'm constrained to as an advanced-level lifter." - Dr. Eric Helms explaining why he does not track a surplus in his bodybuilding off-season once his body fat is above ~10% and his weight settles in the low 90s kg.
• At 1:36:32 - "You're accelerating RED-S by trying to offset the muscle loss from RED-S or that constraint. And one of the symptoms of RED-S and one of the associated things is loss of lean mass, sarcopenia, osteopenia, and actually, experimentally, poor muscle protein synthesis." - Dr. Eric Helms warning against adding extra training volume when dieting at very low body fat levels.
• At 2:02:35 - "Above about 20% body fat, energy isn't your constraint for building muscle. You can sit in a modest deficit, under 400 calories per day, as long as you train hard and you get your protein in, you'll build the maximum amount of muscle while you lose fat. If you were to eat in a surplus, that's mostly going to put on additional fat." - Dr. Jordan Feigenbaum delivering the core actionable guideline for lifters in the higher body fat tertile.
• At 2:03:20 - "If you're over 20% body fat, about 1.6 grams of protein per kilogram body weight gets it done. When you're under 12%, especially if you're not in a surplus, that number tends to climb, probably closer to 2.5 grams of protein per kilogram of body weight." - Dr. Jordan Feigenbaum summarizing how protein targets scale inversely with body fat percentage.

Takeaways

• If you are above ~20% body fat for men (or ~28% for women), train in a modest deficit rather than bulking: Because you have ample endogenous energy reserves, eating in a surplus will mostly add unwanted fat. Sit in a modest calorie deficit (under 400 to 500 kcal/day, ideally 100 to 300 kcal/day), train hard, and eat ~1.6 g/kg/day of protein to maximize muscle growth while losing fat.
• If you are between ~12% and 20% body fat for men (or ~20% to 28% for women), eat around maintenance and focus on training: In this unregulated middle zone, energy availability is not constraining your muscle growth, especially since intermediate/advanced hypertrophy only requires ~40 to 115 kcal/day. Avoid extreme surpluses or deficits, eat intuitively or roughly around maintenance, and focus on progressing your training stimulus.
• If you are below ~12% body fat for men (or ~20% for women), use a small calorie surplus to build muscle: At very low body fat levels, your body defends its fat stores and increases leucine oxidation and gluconeogenesis. To maximize hypertrophy in this state, you must supply exogenous energy via a deliberate, small calorie surplus.
• Increase protein intake to ~2.5 g/kg/day when dieting below ~12% body fat (men) or ~20% (women): While ~1.6 to 1.9 g/kg/day of protein suffices at higher body fat levels, leaner lifters in a calorie deficit experience higher rates of protein oxidation and should increase protein toward ~2.5 g/kg/day to help prevent lean mass loss.
• Do not add training volume to fight muscle loss when you are very lean and in a deficit: Because exercise energy expenditure and tissue repair are on the "energy out" side of the equation, training more when energy-restricted accelerates RED-S, suppresses muscle protein synthesis, and increases muscle loss.
• Move up a weight class if you are a lean, plateaued strength athlete: Drug-tested powerlifters who stay around ~8% body fat and repeatedly water-cut often plateau because their energy availability is constrained (as seen with Taylor Atwood, Panagiotis Tarinidis, Evie Corrigan jumping from 480 kg at 52 kg to 500 kg at 57 kg, Bryce Lewis moving from 93 kg to 105 kg at 5'6", and Feigenbaum jumping from 1,350 lbs at 83 kg to 1,795–1,805 lbs at 93–96 kg). Moving up a weight class relieves the energetic constraint and allows rapid total increases.
• Do not force-feed to match arbitrary height-weight charts: While moving out of a depleted weight class helps, forcing a massive bulk beyond your structural frame backfires—as Helms (6'0") experienced when bulking to 98 kg to chase Boris Sheiko's 120 kg chart, resulting in a bench PR, zero squat or deadlift gains, and passing out on a deadlift after cutting back down.
• Avoid aggressive calorie surpluses if you are a field, court, or track athlete: Following the Garthe et al. findings, eating a ~500 to 600 kcal/day surplus on top of sport conditioning yields negligible extra lean mass or 1RM strength compared to habitual eating, while the resulting fat gain directly impairs sprint speed and vertical jump performance.
• Account for a 2- to 3-month physiological lag period after extreme dieting: If you diet to stage-lean levels, do not expect immediate hypertrophy when reintroducing a surplus. Allow your body time to restore its minimum body fat threshold and normalize bloodwork and endocrine function before expecting contractile tissue accretion.
• Do not rely solely on scale weight to judge whether you are at calorie maintenance: If your body composition is visibly improving and your lifts are progressing at a stable body weight, recognize that trading fat for muscle means you are actually operating in a slight net energy deficit while successfully recompositioning.
• Calibrate your training volume to your current baseline activity rather than generic maximums: While 4+ hard sets per muscle group per week is a solid minimum effective dose for most lifters, recognize that completely detrained individuals can grow from far less, whereas advanced lifters require sustained volume just to prevent losing the muscle they have already built.
• Protect endocrine and gallbladder health during aggressive fat loss phases: Never drop dietary fat below 10 g/day on very-low-calorie diets to avoid bile duct failure, and female lifters should avoid extreme starvation deficits that rapidly disrupt luteinizing hormone (LH) pulsatility and menstrual function regardless of starting body fat.