Weight Loss Calories Insulin or a Third Alternative

Why Do Low Carb Diets Work for Weight Loss? When You Lose Weight on Any Kind of a Diet, Where Does it Go?

Dr. Michael Eades

Discover why low-carb eating changes your body weight in ways “calories in, calories out” cannot fully explain, and how understanding where lost fat actually goes can make weight loss more effective and sustainable.

Summary

In this talk, Dr. Michael Eades explains why low-carbohydrate diets consistently outperform low-fat diets for weight loss and challenges the idea that weight control is only about “calories in, calories out.” He walks through historic starvation and low-carb studies, introduces the concept of metabolic advantage as increased energy expenditure, and then shifts to a “mass balance” perspective that focuses on atoms, not just energy. Using clear examples, he shows that we exhale most of our lost fat as carbon dioxide and argues that the real advantage of low-carb diets is how they alter mass in versus mass out, especially because protein and fat calories are “lighter” than carbohydrate calories per unit of mass. He concludes that despite ongoing academic arguments over exact energy expenditure, real-world trials repeatedly show that low-carb diets lead to greater weight loss and better metabolic health than high-carb, low-fat approaches.

Key points from the video

Low-carb diets consistently outperform low-fat diets for weight loss in real-world randomized trials, with 58 of 67 qualifying studies showing greater weight loss on low carb and 37 showing statistically significant superiority compared with none on low fat.
The traditional “calories in, calories out” model is rooted in the first law of thermodynamics, but Dr. Eades argues this energy-balance framework is the wrong paradigm for understanding changes in body mass.
The so‑called metabolic advantage of low-carb diets is best understood as increased total energy expenditure of roughly 300 kcal per day in some studies, although different research teams debate the exact magnitude using metabolic chambers and doubly labeled water.
According to the carbohydrate–insulin model, high‑glycemic, high‑carb diets drive fat storage via insulin and related hormones, increasing hunger and promoting positive energy balance, whereas low‑carb diets reduce insulin and support fat mobilization.
Meerman and Brown’s work highlights that when we lose fat, most of the lost mass actually leaves the body as exhaled carbon dioxide plus water, meaning we literally “breathe out” our fat rather than convert it into some abstract form of energy.
Dr. Eades introduces a mass balance equation (mass in minus mass out) focused on grams and kilograms, emphasizing that calories themselves have no weight and that different macronutrients provide different grams per kilocalorie.
By inverting Atwater factors, he shows that carbohydrate calories are “heavier” (more grams per kcal) than fat calories, so a high‑carb diet brings more mass into the body than an isocaloric high‑fat, low‑carb diet, which helps explain why low carb can promote more weight loss.
He calls for new research that directly measures mass in and mass out (including water, CO₂, feces, and other outputs) to test mass-balance differences between diets, arguing that this would be more informative than focusing solely on energy expenditure.

Video description

Dr. Michael R. Eades received his BSCE degree in Civil Engineering from California Polytechnic University (Cal Poly), Pomona, California and his MD from the University of Arkansas Medical Sciences (UAMS).

After completing training in General Surgery as UAMS, Dr. Eades (along with his wife) founded Medi-Stat Medical Clinics, a chain of general family medicine outpatient care centers in central Arkansas, where he practiced general family medicine for over a decade.

In 1996, Dr. Eades co-authored (with Mary Dan Eades, MD), their first joint book project ‘Protein Power’, which became a national and international bestseller, selling over 3 million copies and spending 63 weeks on the NY Times Best Seller List.

The Drs. Eades have appeared as guest experts on hundreds of radio and television shows across America. Their work has been featured regionally and nationally on NBC, ABC, CBS, FOX, CNN, MSNBC, and CNBC and seen in such publications as Newsweek, the NY Times, the LA Times, the Washington Post, and USA Today.

Please consider supporting Low Carb Down Under via Patreon. A small monthly contribution will assist in the costs of filming and editing these presentations and will allow us to keep producing high quality content free from advertising. For further information visit; https://www.patreon.com/lowcarbdownunder.

Transcript Summary

Why low-carb works and where fat goes

Dr. Eades begins by asking two questions: why do low-carb diets work for weight loss, and where does fat go when we lose weight on any diet. He previews that he will provide a concrete explanation for low-carb effectiveness that many people have not heard before and notes that this insight grew out of an internet controversy sparked by his blog post “Is a calorie always a calorie?”. The controversy led him to revisit classic studies and rethink whether calories alone can explain differences between starvation, low‑fat diets, and low‑carb eating.

Starvation vs spontaneous restriction on low carb

He describes the Minnesota Starvation Study led by Ancel Keys, in which conscientious objectors were placed on a 24‑week semi‑starvation diet of about 1,570 kcal per day, becoming emaciated, lethargic, and psychologically unstable. He contrasts this with John Yudkin’s work, where young adults following a low‑carb diet spontaneously reduced intake from about 2,330 kcals to roughly 1,560 kcals per day while remaining well-nourished and functional, despite the similar calorie level. This paradox—that the same caloric intake led to severe starvation in one context but good function in another—pushed him to question the simplistic view that “a calorie is a calorie.”

Metabolic advantage and energy expenditure

Eades recounts how the concept of “metabolic advantage” emerged to describe why low‑carb diets appear to burn more calories. In his earlier writing, he estimated that advantage at roughly 300 kcal per day, an estimate later supported by David Ludwig’s randomized study showing about a 300 kcal per day difference in total energy expenditure between low‑carb and high‑carb diets. He clarifies that metabolic advantage is essentially increased energy expenditure: if a 2,000 kcal diet causes you to burn 2,300 kcal, the 300 kcal gap represents the advantage.

Calories in, calories out vs carbohydrate–insulin model

Next, he reviews how researchers measure total energy expenditure using metabolic chambers and doubly labeled water, noting that both methods are expensive and thus limited in use. He summarizes Kevin Hall’s 2016 study comparing a baseline high‑carb, low‑fat diet with a ketogenic diet; depending on the method, the ketogenic phase showed increases of 57 to 151 kcal per day in energy expenditure, which Hall’s group largely downplayed as artifacts. This fueled a back‑and‑forth between “calories in, calories out” advocates and carbohydrate–insulin model proponents, each publishing papers attacking the other’s methods, while real‑world low‑carb trials continued to show superior weight-loss outcomes.

Real-world outcomes favor low carb

Eades highlights a Public Health Collaboration review of 67 trials comparing low‑carb with low‑fat diets. In 58 of the 67 trials, the low‑carb group lost more weight, and in 37 trials, the difference was statistically significant, whereas none of the low‑fat trials showed superior significant weight loss. He emphasizes that regardless of debates about small differences in energy expenditure, the practical evidence shows that low‑carb diets generally “triumph” over low fat for weight loss.

The problem with using the first law of thermodynamics

He then critiques how both sides have framed obesity using the first law of thermodynamics, which concerns conservation of energy, not mass. Quoting Gary Taubes and mainstream authorities, he notes that the standard equation—change in body energy stores equals energy intake minus energy expenditure—has been widely misinterpreted as a direct weight‑change equation. Using an analogy with a kilogram of hot water cooling to room temperature without changing its mass, he argues that calories (heat energy) have no weight, so applying energy-balance equations directly to changes on a bathroom scale is conceptually flawed.

Mass balance: losing atoms, not “burning calories”

Eades introduces Reuben Meerman and Andrew Brown’s work asking “When somebody loses weight, where does the fat go?” and their survey showing that most doctors, dietitians, and trainers wrongly believe fat is lost primarily as energy or heat. Meerman’s TED Talk demonstration uses liquid nitrogen to condense breath and reveal solid carbon dioxide, illustrating that the carbon atoms from food are exhaled as CO₂, with only a fraction leaving via water, feces, and other routes. Building on this, Eades proposes thinking in terms of a mass‑balance equation—change in body mass equals mass in minus mass out—where the key outputs include CO₂, water, ketones, methane, and other measurable substances.

Inverting Atwater factors: heavy vs light calories

He revisits Wilbur Atwater’s classic factors of approximately 4 kcal per gram for protein and carbohydrate and 9 kcal per gram for fat, noting that these were originally controversial because they implied similar metabolic rules in animals and humans and recognized alcohol as a source of calories. Eades then “inverts” these factors to express grams per kilocalorie, yielding roughly 0.25 g/kcal for protein and carbohydrate and 0.11 g/kcal for fat, and labels carb and protein calories as “heavy kcals” and fat calories as “light kcals.” This inversion lets him compare diets of equal calories but different macronutrient compositions in terms of total mass entering the body.

How macronutrient mix changes mass intake

Using a thought experiment, he shows that a person consuming 1,095,000 kcal per year entirely from carbohydrate would ingest about 603 pounds of pure carbohydrate mass, whereas the same number of calories entirely from fat would yield about 265 pounds of fat mass. The difference—about 338 pounds of mass—illustrates how a high‑carb diet can bring substantially more mass into the body than an isocaloric high‑fat diet. In more realistic mixed diets, he compares a 2,500 kcal low‑fat, high‑carb diet (55 percent carb, 30 percent fat, 15 percent protein) with a low‑carb, high‑fat diet (10 percent carb, 75 percent fat, 15 percent protein) and estimates that the low‑fat eater brings in about 520 grams of macronutrient mass per day versus about 363 grams on the low‑carb diet, a difference of roughly one‑third of a pound daily.

Implications for weekly weight loss

Multiplying that daily mass difference over a week yields around 2 to 2.5 pounds of mass difference, matching the kind of weight loss Eades aims for in low‑carb clinical practice. He stresses that these are theoretical calculations but that they align with observed low‑carb weight‑loss rates and help explain why low‑carb diets can outperform low‑fat diets even when calories are matched. He also notes that low‑carb diets often involve foods with higher water content, such as meat, which may contribute to early fluid losses alongside sodium changes when insulin drops.

Limits of existing data and call for better studies

Eades describes trying to reanalyze Kevin Hall’s metabolic chamber and doubly labeled water datasets to calculate precise mass in versus mass out but finding that key variables, such as water volume and measured feces mass, were missing. His rough calculations still suggested differences consistent with his mass balance argument, but he emphasizes that proper studies could and should measure all relevant inputs and outputs directly. He expresses surprise that only one highly mathematical paper by R.N.C. Baliguet had addressed this kind of mass-balance approach in the scientific literature, while obscure supplements have dozens of PubMed entries, suggesting that a fundamental question has been largely neglected.

The “third alternative”: from energy balance to mass balance

He closes by returning to Max Kleiber’s warning that overgrown hypotheses can create confusion instead of clarity and praises Alfred Pennington’s experience of suddenly seeing obesity mechanisms fall into place with a new concept. For Eades, that new concept is shifting from an energy‑balance paradigm to a mass‑balance paradigm that recognizes we lose fat by excreting atoms and that macronutrient composition changes both mass intake and hormonal regulation of fat storage. In his view, this “third alternative” beyond “calories only” and “insulin only” integrates energy expenditure, carbohydrate–insulin effects, and the physics of mass in versus mass out to explain why low‑carb diets so reliably improve weight and metabolic health.