Critics of the Carbohydrate-Insulin Model built a new Energy Balance Model of obesity.
My 15 coauthors and I have a few thoughts about it. @ejcneditor @SpringerNature #CarbInsulinModel
New review open access at this link 👇👇👇
doi.org/10.1038/s41430…
Thread 1/16
My 15 coauthors and I have a few thoughts about it. @ejcneditor @SpringerNature #CarbInsulinModel
New review open access at this link 👇👇👇
doi.org/10.1038/s41430…
Thread 1/16
Models Have Opposing Views of Cause & Effect
👉Energy Balance Model: overeating CAUSES obesity
👉Carb-Insulin Model: process of getting fat (energy partitioning) CAUSES overeating
Consider adolescent growth spurt: Overeating is a consequence, not cause, of rapid growth
2/16
👉Energy Balance Model: overeating CAUSES obesity
👉Carb-Insulin Model: process of getting fat (energy partitioning) CAUSES overeating
Consider adolescent growth spurt: Overeating is a consequence, not cause, of rapid growth
2/16
The Models Have Clearly Contrasting Features
👉Claims that the CIM is just a "special case" of the EBM muddle paradigm testing and refinement.
As Karl Popper reportedly said, “a theory that explains everything, explains nothing.”
3/16
👉Claims that the CIM is just a "special case" of the EBM muddle paradigm testing and refinement.
As Karl Popper reportedly said, “a theory that explains everything, explains nothing.”
3/16
Drivers of Obesity in New Energy Balance Model
New EBM blames "energy-dense, ultra-processed foods that are high in portion size, fat, and sugar, and low in protein and fiber"
Several of these (sugar, fiber, protein) are also in the CIM. What about the others?
4/16
New EBM blames "energy-dense, ultra-processed foods that are high in portion size, fat, and sugar, and low in protein and fiber"
Several of these (sugar, fiber, protein) are also in the CIM. What about the others?
4/16
ENERGY DENSITY
Major short term BUT NO chronic effect:
n=97, 1 yr: no diff body fat pubmed.ncbi.nlm.nih.gov/17556681/
n=2718, 4 yr: no diff weight pubmed.ncbi.nlm.nih.gov/18444133/
n=200, 1 yr: small wt diff. But high ED group given more high GI carbs (confounded) pubmed.ncbi.nlm.nih.gov/15976148/
5/16
Major short term BUT NO chronic effect:
n=97, 1 yr: no diff body fat pubmed.ncbi.nlm.nih.gov/17556681/
n=2718, 4 yr: no diff weight pubmed.ncbi.nlm.nih.gov/18444133/
n=200, 1 yr: small wt diff. But high ED group given more high GI carbs (confounded) pubmed.ncbi.nlm.nih.gov/15976148/
5/16
DIETARY FAT
We tried low-fat in the last version of the EBM, late 20th century.
Low-fat diets are, if anything, inferior to higher fat comparisons.
pubmed.ncbi.nlm.nih.gov/26527511/
6/16
We tried low-fat in the last version of the EBM, late 20th century.
Low-fat diets are, if anything, inferior to higher fat comparisons.
pubmed.ncbi.nlm.nih.gov/26527511/
6/16
FOOD PROCESSING
Important but EBM misses key effect of macronutrients:
👉Processing carbs greatly speeds digestion rate, causes adverse health effects
👉Processing of proteins/fats, little evidence of harm
Concept of ultra-processing better explained by CIM than EBM
7/16
Important but EBM misses key effect of macronutrients:
👉Processing carbs greatly speeds digestion rate, causes adverse health effects
👉Processing of proteins/fats, little evidence of harm
Concept of ultra-processing better explained by CIM than EBM
7/16
EBM ANOMALIES #1
EBM says modern foods act on “reward, appetite, sensory processing” in brain. But all calories are alike to the body.
👉So why does weight reduction to a typical, easily maintained weight 50 yr ago cause the body to resist (eg slowing energy expenditure)?
8/16
EBM says modern foods act on “reward, appetite, sensory processing” in brain. But all calories are alike to the body.
👉So why does weight reduction to a typical, easily maintained weight 50 yr ago cause the body to resist (eg slowing energy expenditure)?
8/16
EBM ANOMALIES #2
Obesity usually develops slowly, average 1 to 2 gram/d extra fat deposited (< 20 kcal/d)
Energy intake is only 200 kcal/d greater now than 1970 (tall glass OJ)
👉Why is it so hard for people to compensate through conscious control for such small effects?
9/16
Obesity usually develops slowly, average 1 to 2 gram/d extra fat deposited (< 20 kcal/d)
Energy intake is only 200 kcal/d greater now than 1970 (tall glass OJ)
👉Why is it so hard for people to compensate through conscious control for such small effects?
9/16
EBM ANOMALIES #3
Since 2000, obesity rates still rising rapidly
Has "overeating" driven the increase? Perhaps not:
👉Calories in food supply haven't increased. Average energy intake appears to have DECREASED!
(Physical activity level not lower)
pubmed.ncbi.nlm.nih.gov/35460220/
10/16
Since 2000, obesity rates still rising rapidly
Has "overeating" driven the increase? Perhaps not:
👉Calories in food supply haven't increased. Average energy intake appears to have DECREASED!
(Physical activity level not lower)
pubmed.ncbi.nlm.nih.gov/35460220/
10/16
EBM ANOMALIES #4
In many animal obesity examples, weight gain occurs even with food restriction to PREVENT OVEREATING
These examples address critical distinction between models:
👉Underlying metabolic defects drive fat storage independent of calorie intake (c/w CIM)
11/16
In many animal obesity examples, weight gain occurs even with food restriction to PREVENT OVEREATING
These examples address critical distinction between models:
👉Underlying metabolic defects drive fat storage independent of calorie intake (c/w CIM)
11/16
MODEL REVISION
New EBM disparages CIM for abandoning precepts (it hasn't)
Yet EBM has undergone big revisions:
👉Calorie counting, early 20th C
👉Low fat, late 20th C
👉Now, host of modern dietary factors
For models to be relevant they must grow as new evidence accrues
12/16
New EBM disparages CIM for abandoning precepts (it hasn't)
Yet EBM has undergone big revisions:
👉Calorie counting, early 20th C
👉Low fat, late 20th C
👉Now, host of modern dietary factors
For models to be relevant they must grow as new evidence accrues
12/16
EBM Improvements for Constructive Paradigm Clash, #1
👉Provide explicit testable hypothesis that differentiate the proposed causal pathway (overeating drives chronic weight gain) from the contrasting hypothesis in the CIM
13/16
👉Provide explicit testable hypothesis that differentiate the proposed causal pathway (overeating drives chronic weight gain) from the contrasting hypothesis in the CIM
13/16
EBM Improvements for Constructive Paradigm Clash, #2
👉Avoid assumptions that don't differentiate among models
New EBM interprets evidence that brain controls weight as supporting a causal role of overeating. But brain also influences metabolism and adipocyte function.
14/16
👉Avoid assumptions that don't differentiate among models
New EBM interprets evidence that brain controls weight as supporting a causal role of overeating. But brain also influences metabolism and adipocyte function.
14/16
EBM Improvements for Constructive Paradigm Clash, #3
👉Explain recognized metabolic mechanisms
Energy restriction elicits hallmarks of starvation response long before body fat stores reach normal. How do hedonic, reward aspects of tasty food trigger metabolic responses?
15/16
👉Explain recognized metabolic mechanisms
Energy restriction elicits hallmarks of starvation response long before body fat stores reach normal. How do hedonic, reward aspects of tasty food trigger metabolic responses?
15/16
👉"All sides of this debate should work together to formulate mutually agreeable versions of competing models and design unbiased studies"
👉This is "facilitated with the recognition that...[obesity pathogenesis] may entail elements of both" models
doi.org/10.1038/s41430…
16/16
👉This is "facilitated with the recognition that...[obesity pathogenesis] may entail elements of both" models
doi.org/10.1038/s41430…
16/16
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