Calories are king for fat loss — the reason both carnivore and vegan diets 'work' is that both can produce a calorie deficit; Israetel recommends cutting 250–500 calories below your personal maintenance intake.
2
Skip TDEE equations (Harris-Mifflin can be off by ±700 calories per person); instead log one week of food in MyFitnessPal at a stable body weight to find your real maintenance, then subtract ~350 calories from that number.
3
Resistance training is not optional during a fat-loss diet — without it, you lose significant muscle even at high protein intakes, because protein sparing from diet alone requires the mechanical stimulus of lifting.
4
GLP-1 drugs like Ozempic produce muscle loss proportional to total weight lost, not as a specific drug effect; a new review found the loss is exactly what you'd expect from losing 50 pounds in any context — and resistance training counters it.
Protocols
Concrete recipes — what, when, how much, and why
5 items
1-week food log to find personal maintenance calories
WhatLog every meal and drink in MyFitnessPal for 7 consecutive days while your body weight is stable (no active diet). At the end of the week, look at the average daily calorie intake the app reports. That number IS your maintenance.
WhenBefore starting any fat-loss phase. Also useful when fat loss has stalled — re-log to check for calorie creep.
Dose7 days of logging at stable weight. Takes 5–10 minutes per day.
For whomAnyone starting a fat-loss phase who doesn't know their actual maintenance intake. Especially useful if previous deficit attempts failed despite 'following the equation.'
WhyYour actual food intake at a stable weight is a 'completely integrated measurement' — it accounts for hormones, digestion, NEAT, thermic effect of food, and everything else that TDEE equations miss. It makes zero assumptions.
CaveatsAccuracy requires honest logging — everything in, including cooking oils, sauces, drinks. One week gives a reliable average as long as weight is not actively moving.
Israetel explicitly rejects Harris-Benedict and Mifflin-St Jeor equations: 'There are a bunch of factors they can't account for and people tend to view equations as very precise things — so once they get their number they're like well I've been eating 1900 calories but I'm not losing weight, what's wrong?' The error tolerance of those equations is ±700 calories per person — larger than most intended deficits. The food-log approach is self-calibrating: if your weight is stable while eating X calories, X is your maintenance, full stop. Israetel's analogy: 'it's like taking off time and landing time on an airplane — you don't need a working speedometer if you can measure start and end.'
Mechanism
Body weight homeostasis means that at a stable weight, energy in = energy out (with measurement error < 50 calories/day). Your food log captures the 'energy in' side; stability of weight confirms the 'energy out' side is matched.
Just get MyFitnessPal and type in for a week everything you eat and then it's just going to tell you how many calories you're eating and macros proteins carbs fats and you just take like 350 away from that number.
250–500 calorie daily deficit from personal maintenance
WhatOnce you know your personal maintenance from the food log, reduce daily intake by 250–500 calories. The lower end (250) is gentler and better for muscle preservation; the upper end (500) is appropriate for people who are significantly overweight and can tolerate a faster pace.
WhenSustained daily during a fat-loss phase. Does not require calorie cycling, refeed days, or diet breaks at this level unless the phase extends beyond 8–12 weeks.
Dose250–500 calories below maintenance, daily. Israetel gives the concrete example: subtract ~350 from your logged maintenance number to find your target.
For whomGeneral fat-loss population. Women with lower absolute calorie needs should use the lower end of the range (250 cal) to avoid dropping below ~1,200 calories.
WhyThis range produces approximately 0.5–1 lb of fat loss per week — fast enough to be motivating and metabolically meaningful, slow enough to preserve muscle mass and hormonal function.
CaveatsDoes not account for changes in NEAT (spontaneous movement) during a diet, which often drops and partially offsets the deficit. If fat loss stalls after 2–3 weeks, re-log to check for calorie creep or re-calculate with a fresh food log.
The example Lyon and Israetel work through: a woman maintaining at 1,800 calories drops to ~1,450 (350 cal deficit) to start. Israetel's range tops out at 500 calories below maintenance for 'extreme' cases. Going deeper than 500 below maintenance drives faster muscle loss, metabolic adaptation, and adherence failure — the tradeoffs rapidly become unfavorable. The magic is in the modesty: 'If you eat a few hundred calories less for a few months you will almost certainly lose weight and improve your health.'
Typically cutting somewhere between 250 and maybe 500 at the extreme calories daily from your typical intake is a really good situation to have.
Also said
“If you eat a few hundred calories less for a few months you will almost certainly lose weight and improve your health and so on and so forth.”— The simplicity is the point — sustained modest deficit beats aggressive short-term restriction.
Resistance training as the required co-intervention during fat loss
WhatBegin or maintain a resistance training program (lifting weights, compound movements) throughout any fat-loss phase. This is not optional — it is the primary tool for determining whether the weight lost comes from fat or muscle.
WhenStart simultaneously with the calorie deficit, not after. Even 2–3 sessions per week of full-body lifting is sufficient to change the composition of weight lost.
DoseMinimum 2–3 sessions/week of progressive resistance training. Intensity and volume should be sufficient to provide a genuine muscle stimulus (i.e., sets near failure on compound movements).
For whomEveryone in a fat-loss phase, but especially: (1) previously untrained individuals who can achieve simultaneous fat loss and muscle gain; (2) lean individuals who otherwise would lose significant muscle during any deficit.
WhyWithout the mechanical stimulus of resistance training, dietary protein does not spare muscle — it is simply oxidized and excreted. With lifting, protein is directed to muscle protein synthesis and muscle mass is preserved or even increased during a deficit.
CaveatsBeginners get a larger benefit — they can gain muscle while losing fat for months to years. Trained athletes in a deficit will preserve muscle but not gain it without anabolic support.
Israetel: 'If both groups start weight training when they start losing weight then they just build muscle and lose fat at the same time. That's a really really big deal.' The untrained-beginner case is particularly compelling: start a calorie deficit AND resistance training simultaneously and you can build a leaner, more muscular body simultaneously for an extended period. Israetel notes this was covered in detail on a prior Lyon show appearance. The mechanism — and this is Israetel's key teaching — is that the protein-sparing effect requires the training stimulus: 'without activity, without muscular specific training, protein doesn't have a terribly protein sparing effect.'
Mechanism
Resistance training upregulates mTORC1 signaling and muscle protein synthesis, directing ingested amino acids toward lean mass accretion or preservation rather than oxidation. Without this signal, dietary protein is metabolized like any other calorie.
If both groups start weight training when they start losing weight then they just build muscle and lose fat at the same time. That's a really really big deal.
Reframe GLP-1 use: pair anorectic drugs with resistance training to protect lean mass
WhatIf using GLP-1 agonists (Ozempic, Wegovy, etc.) for weight loss, pair the drug with a resistance training program from day one. The muscle loss attributed to these drugs is a weight-loss-magnitude effect, not a drug-specific catabolic effect — and resistance training counters it.
WhenFrom the start of GLP-1 use. Waiting until muscle loss is noticed is too late.
For whomAnyone using GLP-1 drugs for weight loss. Also useful framing for clinicians advising patients on semaglutide — the co-prescription of resistance training should be standard.
WhyA new review shows that Ozempic-associated muscle loss is proportional to total weight lost — exactly what you'd predict from any 50-lb weight loss regardless of method. The drug does not cause extra muscle loss; the rapid, large-magnitude weight loss it enables does. Adding resistance training shifts the composition of weight lost toward fat.
CaveatsGLP-1-induced appetite suppression can reduce protein intake; monitoring protein sufficiency and adding resistance training are both necessary to maintain lean mass.
Israetel: 'One of the new anorectic drugs Ozempic got a little bit of hot water because people were like it's causing people lots of muscle mass loss. It was true but it was no more muscle mass loss than you would expect with people who lost like 50 pounds in a year.' He is broadly favorable on anorectic drugs — 'they do have a big role to play in all this' — while consistently pointing back to resistance training as the required co-intervention. Lyon agrees. The clinical implication: the muscle-loss concern is valid but attributable to the magnitude of weight loss, not the mechanism of the drug, and is therefore addressable with the same intervention that addresses muscle loss from any rapid diet.
It was no more muscle mass loss than you would expect with people who lost like 50 pounds in a year. It's just going to be a lot of muscle loss. It's not especially a thing that GLP-1s even do.
Choose the diet style that lets you sustain the 250–500 cal deficit, not the one with the best science marketing
WhatAmong diets that hit your protein targets and produce a 250–500 calorie deficit, choose the one you can actually adhere to for months. Carnivore, vegan, Mediterranean, keto — the mechanism doing the fat-loss work is the deficit, not the label.
WhenDiet selection phase, before starting. Also when a current diet is failing on adherence.
For whomAnyone overwhelmed by conflicting diet advice. Also useful for people who have done well on an 'unusual' diet and worry it is somehow wrong.
WhyBoth carnivore and vegan diets produce blood work improvements when followed strictly. The commonality is the calorie deficit both approaches tend to enforce. The specific macronutrient distribution or food exclusion list is not the mechanism.
Israetel: 'On kind of evidence-based Fitness — if you're taking care of your calories getting that little deficit going and a few other things a little quality control type of stuff — there's many ways to get there and you don't have to be super dogmatic about like it's only this one. There's tons.' The 'quality control' he references includes adequate protein and micronutrient completeness. But within those constraints, adherence trumps composition purity. The person who sustains a 300-calorie deficit on an impure mixed diet for 6 months will outperform someone who follows a perfect protocol for 3 weeks then quits.
On kind of evidence-based Fitness — if you're taking care of your calories getting that little deficit going and a few other things a little quality control type of stuff — there's many ways to get there and you don't have to be super dogmatic about it.
What's new
Personal practice updates, fresh positions, predictions
5 items
Calorie tracking from a stable-weight food log beats any TDEE equation
Harris-Mifflin and similar equations can vary in accuracy by up to ±700 calories per individual — meaning someone could be in a surplus or a deficit without knowing it. The superior method: log every meal in MyFitnessPal for one week while body weight is stable, then use the resulting average as your personal maintenance number, and subtract 250–500 calories.
Why this matters: Most diet failures stem from trusting equations that are wrong for the individual. The food-log method is a completely integrated measurement — it captures hormones, digestion, NEAT, everything — and makes zero assumptions.
Background
The Harris-Benedict / Mifflin-St Jeor equations were built on population averages and cannot account for individual variation in NEAT, gut absorption, thyroid status, or activity level.
Israetel frames the food log as analogous to taking off time and landing time on an airplane flight: you don't need a working speedometer if you can measure start and end. 'The actual calories you're eating assuming your body weight's relatively stable — that's what we would call a completely integrated measurement. It integrates every single aspect: hormones, diet, lifestyle, food choices, digestion, non-exercise activity thermogenesis, the whole thing. It makes zero assumption.' Once you know your maintenance from a logged stable week, the deficit is simple arithmetic. This approach sidesteps the single biggest source of diet failure: trusting a formula that's wrong for you personally by 700 calories.
The actual calories you're eating assuming your body weight's relatively stable — that's what we would call a completely integrated measurement. It integrates every single aspect hormones diet lifestyle food choices digestion non exercise activity thermogen the whole thing it makes zero assumption.
Also said
“The Harris Mifflin equation or whatever — that's actually an estimate that varies in accuracy by 700 calories person up and down. So you could be in a surplus or deficit, who knows.”— Quantifies exactly how wrong equations can be — the margin of error swallows most intended deficits.
250–500 cal/day deficit is the evidence-based sweet spot — not starvation, not eating ad libitum
Israetel's recommended deficit range is 250–500 calories below personal maintenance per day. This range is large enough to produce visible fat loss over weeks but small enough to avoid the muscle loss, hormonal suppression, and dietary adherence collapse that come with aggressive cuts.
Why this matters: The range is deliberately modest — most people's instinct is to cut 700–1,000+ calories, which accelerates muscle loss and triggers metabolic adaptation.
Lyon's example patient: a woman whose maintenance is 1,800 calories drops to 1,300–1,450 (a 350–500 calorie deficit). Israetel confirms this is the correct range and declines to complicate it by breaking out exercise calories separately — the food log already integrates activity. The key insight: 'if you eat a few hundred calories less for a few months you will almost certainly lose weight and improve your health.' The simplicity is the point; elaboration adds noise without adding fat loss.
Typically cutting somewhere between 250 and maybe 500 at the extreme calories daily from your typical intake is a really good situation to have.
Calorie deficit explains why carnivore AND vegan diets both 'work' simultaneously
The reason carnivores and vegans can both point to bloodwork improvements and body composition changes is that both diets, when followed strictly, tend to produce a calorie deficit. The mechanism is not the macronutrient ratio or the exclusion list — it's the deficit that both approaches accidentally enforce.
Why this matters: Reframes the diet-war debates: any diet that produces a sustained 250–500 calorie deficit will produce fat loss, and the 'magic' attributed to specific food lists is almost entirely a deficit effect.
Israetel: 'You'll have carnivores and vegans in comment sections yelling at each other. They both have great blood work after and all this stuff. And the thing is the calorie deficit is really that thing doing most of the work.' The practical upshot is that diet selection should be driven by long-term adherence — whatever style of eating makes it easiest for you to maintain the 250–500 deficit is the right diet for you, not the one with the most zealous online community.
You'll have carnivores and vegans in comment sections yelling at each other... they both have great blood work after and all this other stuff and the thing is the calorie deficit is really that thing doing most of the work.
Resistance training is essential during fat loss — protein alone does NOT spare muscle without lifting
A common misconception is that eating high protein protects muscle during a deficit. Israetel is clear: without the mechanical stimulus of resistance training, even 300 grams of protein per day does not prevent significant muscle loss. The protein simply gets oxidized and excreted. Lifting changes the equation entirely — beginners can gain muscle and lose fat simultaneously for months to years.
Why this matters: Challenges the 'just eat more protein' simplification common in fat-loss advice. The stimulus signal matters as much as the substrate.
Background
The protein-sparing effect of dietary protein requires muscle protein synthesis to be upregulated by training — without that upstream signal, protein is just another calorie source.
Israetel: 'Protein has a protein sparing effect but without activity, without muscular specific training, it's actually protein doesn't have a terribly protein sparing effect. You can't eat 300 grams of protein if you don't lift weights — it actually just gets burned and excreted.' The implication: for anyone doing a fat-loss phase, resistance training is not an optional add-on for aesthetics. It is the primary mechanism that determines whether weight lost is fat or muscle. Lyon and Israetel both agree this is the most underappreciated variable in fat-loss programs aimed at women.
Protein has a protein sparing effect but without activity without muscular specific training it's actually protein doesn't have a terribly protein sparing effect. You can't eat 300 grams of protein if you don't lift weights — it actually just gets burned and excreted.
Also said
“If both groups start weight training when they start losing weight then they just build muscle and lose fat at the same time. That's a really really big deal.”— The positive flip side: lifting doesn't just prevent muscle loss, it can flip the equation to simultaneous muscle gain.
GLP-1 muscle loss is a weight-loss effect, not a drug effect — new review confirms proportionality
Ozempic/semaglutide received bad press for causing muscle mass loss. Israetel cites a new review showing the muscle loss was proportional to total weight lost — exactly what you'd predict from any 50-lb weight loss, regardless of method. GLP-1 drugs are not specially catabolic; the concern is that they enable rapid, large-magnitude weight loss that, without resistance training, loses the expected amount of muscle.
Why this matters: Reframes the GLP-1 muscle-loss debate: the issue is not the drug, it's the absence of resistance training. Add lifting and the equation changes.
Israetel: 'It was no more muscle mass loss than you would expect with people who lost like 50 pounds in a year. It's just going to be a lot of muscle loss. It's not especially a thing that GLP-1s even do. And there's actually a new review that came out that was exactly what we would expect if you just lost a lot of weight.' His overall position on anorectic drugs is favorable — 'they do have a big role to play in all this' — while emphasizing that resistance training is the required co-intervention to protect lean mass at any weight-loss magnitude.
It was no more muscle mass loss than you would expect with people who lost like 50 pounds in a year. It's just going to be a lot of muscle loss. It's not especially a thing that GLP-1s even do.
Recommendations
Products, supplements, and tools mentioned in the episode
2 items
MyFitnessPal (food logging app)
Tool
Israetel explicitly recommends MyFitnessPal (by name) as the tool for the 1-week baseline food log. The app tracks calories and macros (protein, carbs, fat) and gives you your actual intake without relying on equations.
Israetel: 'Just get MyFitnessPal and type in for a week everything you eat and then it's just going to tell you how many calories you're eating and macros proteins carbs fats and you just take like 350 away from that number and voila you're well on your way.' The tool is generic — any accurate food-tracking app works — but MyFitnessPal is the specific named recommendation and is appropriate given its large food database and ease of barcode scanning.
Just get MyFitnessPal and type in for a week everything you eat and then it's just going to tell you how many calories you're eating and macros proteins carbs fats.
Resistance training program (concurrent with fat loss diet)
Practice
Both Lyon and Israetel recommend beginning or maintaining a resistance training program simultaneously with any calorie-deficit fat-loss phase. This is framed as the essential co-intervention, not an optional add-on.
Israetel covered resistance training programming for fat loss in a prior Lyon episode (referenced as 'my last appearance here on the show'). The current episode adds the specific mechanism: protein cannot spare muscle without the mechanical stimulus of lifting. The practical prescription: 2–3 sessions per week minimum, compound movements, progressive overload.
When they start getting a healthy diet higher in protein and they start lifting weights then they can actually gain muscle and lose fat at the same time for months and months if not years.
Evidence-Based Fitness (RP Strength) content channel by Dr Mike Israetel
Practice Sponsored · disclosed
Israetel repeatedly frames his recommendations as coming from 'evidence-based Fitness' — a reference to his RP Strength platform, which offers online training programs, nutrition coaching, and educational content for hypertrophy, fat loss, and sport performance.
DisclosureIsraetel is the co-founder of Renaissance Periodization (RP Strength) and references 'evidence-based Fitness' as the framework he promotes.
Israetel's PhD is in exercise physiology and he has taught nutrition at a university level before transitioning to RP Strength. His approach is explicitly non-dogmatic: 'there's many ways to get there and you don't have to be super dogmatic about like it's only this one.' His content (YouTube, RP App, books) is built around applying the research literature to practical programming — appropriate for anyone wanting to go deeper than the principles discussed in this episode.
One thing we try to promote on kind of evidence-based Fitness is you know if you're taking care of your calories getting that little deficit going and a few other things a little quality control type of stuff — there's many ways to get there.
Lines worth pulling out — contrarian, specific, or perfectly phrased
5 items
Calories are king. If you eat a few hundred calories less for a few months you will almost certainly lose weight and improve your health.
Israetel's core thesis in two sentences — the simplest accurate statement of fat-loss science for a general audience.
The Harris Mifflin equation varies in accuracy by 700 calories person up and down. So you could be in a surplus or deficit, who knows.
The number (±700 calories) is the key reason equation-based diets fail — the error margin swallows the intended deficit.
Protein has a protein sparing effect but without activity, without muscular specific training, it's actually protein doesn't have a terribly protein sparing effect. You can't eat 300 grams of protein if you don't lift weights — it actually just gets burned and excreted.
Debunks the 'just eat more protein to keep muscle on a diet' claim — the mechanical stimulus of lifting is required, not just the substrate.
It was no more muscle mass loss than you would expect with people who lost like 50 pounds in a year. It's not especially a thing that GLP-1s even do.
Cleanly reframes the GLP-1 muscle-loss panic: the issue is weight-loss magnitude, not drug pharmacology.
If both groups start weight training when they start losing weight then they just build muscle and lose fat at the same time. That's a really really big deal.
The counter-argument to fat-loss inevitably requiring muscle sacrifice — lifting changes the equation entirely, especially for beginners.
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Educational summary of the cited expert source — not medical advice. Open the source recording linked above and consult a qualified physician before acting on any protocol.
