Here’s some thoughts I have on the Calories In/Calories Out (CICO) model.
The CICO perspective has value but I think where Fung’s contribution worked for me and others was the role of Insulin in weight gain and carbs being the driving force in Insulin Resistance. Combining Low Carb with Intermittent Fasting made for easy compliance. The reduction of Insulin levels over extended periods of time frees the body to release body fat. The release of body fat reduces the need for calories from the diet since part of the fuel that body needs comes from the body rather than meals.
I see Fung’s advice as focused on his patient population which as a kidney doctors is many older diabetic patients. He found that his patients were compliant with Intermittent Fasting and Low Carbohydrate diets. Probably much more so than the standard population because they were seeing a kidney doctor to begin with. Faced with the possibility of failing kidneys or eating OMAD/Low Carb the alternative seems pretty bad.
Also, there are differences in body composition between various diets. Some are more effective than others at shifting the lean mass/fat mass proportions. http://www.ergo-log.com/paleo-diet-makes-fat-cells-lazy.html
I think they do matter but not so much at the start of the diet. Eventually we have to pay attention to them when we stall with lazy keto. But I got from 285 to around 220 with being completely lazy keto. Never would have reached goal weight, though.
Put another way when we have 100 lbs of body fat that’s 3100 calories a day of fat we can easily pull from our fat stores. Easy to do a caloric “deficit” since we have plenty of surplus to draw from in our bodies.
I’ve been looking into the three compartment theory of diabetes and it seems to have legs to me. First our body’s fat cells fill up. Then our liver fills up with fat. Last our pancreas gets choked with fat which keeps us from making enough Insulin. When that happens our fat backs up into our blood in the form of very high triglycerides. When I was Dx with T2D my triglycerides were over 5000. In fact, they couldn’t get an assay on the number since it was too high. Putting someone on Insulin gets them over that by allowing the fat cells to get even fatter. I gained 50 lbs when the doctor put me on Insulin and my diet was not any different.
This has application in this situation since the fat cells stay locked closed due to high Insulin. There are studies which show CICO doesn’t exactly apply in these cases. Diabetics take more Insulin and eat less calories but still gain weight. There’s a strong relationship with Insulin and body fat.
Intermittent fasting and Low Carb break that relationship by lowering basal Insulin levels and allow the liver to begin dumping the fat. That only takes about a week. The pancreas gets less fatty within 2 weeks and the body’s fat cells drop thereafter.
To me the key is the role of Insulin and that’s Fung’s “contribution”. He’s not a researcher but applied what he learned in the clinical setting.
Bottom line is that if someone is Type 2 Diabetic they can get off meds very quickly by following Fung’s approach of Intermittent Fasting and Low Carb. They can learn to count calories/macros later on when they stall if they want to get lower in weight (and some of them may not care about their weight, they just want to be no longer diabetic).
The reason I think CICO matters later on is that our hormones, particularly Insulin, get in order and then the standard model applies.
There are studies which also show CICO is not matched by the data. For example: https://academic.oup.com/jcem/article/88/4/1617/2845298
The mechanism of the enhanced weight loss in the very low carbohydrate diet group relative to the low fat diet group is not clear. Based on dietary records, the reduction in daily caloric intake was similar in the two groups. For the greater weight loss in the very low carbohydrate group to be strictly a result of decreased caloric consumption, they would have had to consume approximately 300 fewer calories/d over the first 3 months relative to the low fat diet group.
I think Protein is the power multiplier between Low Carb and SAD. In part it has something to do with the Thermic Effect of Food with Protein using about 25% of the calories to process and fat and carbs being much less. So Calories in and Calories out need to take into account the source of the calories.
I’m eating about 2800 calories a day now on Carnivore diet with around 280g of Protein a day. Far in excess of my “Needs”. Some of that we just eliminate as Urea – again outside of the CICO model.
Or maybe the CICO model is just really, really complicated compared to what we see on the standard calculators?
My guess is that the standard calculations for BMR and TDEE are inherently based on the SAD macro ratios. They don’t correct for overconsumption of protein nor do they correct for underconsumption of carbohydrates. They don’t take into account hormonal factors either nor medications such as Insulin.
They are good first order approximations. Eat and track macros and by extension calories. Watch the scale. If you are gaining you need to cut back. If you are maintaining then things are set pretty close. If you want to lose you need to cut.
In my case my methodology is:
Less than 20 g of carbs
At least 1 gram of protein per lb of Lean Body Mass
Enough fat to fill the gap between the first 2 and what I want to lose.
Here’s the calculator I wrote to calculate macros.