If this is worthwhile in it's own right, then what do you think it showed in the end? Serious question. I appreciate that you tracked so much data, but could you interpret it?
Because it seems to show, contrary to something I think you stated earlier (apologies if not so), that a "calorie restricted diet is not a calorie restricted diet."
I'm not trying to be snarky, but I think maybe this would advance the conversation, as long as we're going to keep talking potatoes. Also someone removed the key from the built-in lock on the back wheel of my bike, so it's unusable and I'm walking everywhere, so I'm pissed, so if this reads as snark I can't help it right now. Anyway...
I believe that the data shows a number of things, in no particular order :
- Weight fluctuates, even when one ingests the same bland meal over and over again.
- Water retention is something that needs to be accounted for.
- Anecdotal and subjective evidence is not evidence. Metrics need to taken.
- Metabolizable energy must be accounted for.
- Gross energy expenditure / metabolic rate is probably highly exaggerated by conventional models.
Now, I have a lot more to say about point 4 in particular, but I want to bang out a post for my blog, rather than put it here, as I've already been accused of "spamming" MDA.
Now, when I say, "bang out" this might be interpreted to mean as me doing that quickly, but I'm afraid that I have a bunch more reading to do, as well as dealing with some personal things. Nothing overly traumatic, I'm moving, so I'm in middle of a packing / unpacking cycle which is far from my preferred way of spending my time, but ... c'est la vie.
A large russet potato has 290 calories and 8 grams of protein.
A modest calorie restricted daily amount of 1900 calories for a adult male would be the equivalent of 6.5 large russet potatoes ,which would be the equivalent of 52 grams of protein. Which is right in line with 50g minimum protein you seem to have ignored with your implied zero protein potatoes.
Potatoes and Human Health, Part IFor some bizzarro universe definition of "nutrient-dense." Maybe as compared to styrofoam ... ?
From a nutritional standpoint, potatoes are a mixed bag. On one hand, if I had to pick a single food to eat exclusively for a while, potatoes would be high on the list. One reason is that they contain an adequate amount of complete protein, meaning they don't have to be mixed with another protein source as with grains and legumes. Another reason is that a number of cultures throughout history have successfully relied on the potato as their principal source of calories, and several continue to do so. A third reason is that they're eaten in an unrefined, fresh state.
Potatoes contain an adequate amount of many essential minerals, and due to their low phytic acid content (1), the minerals they contain are well absorbed. They're rich in magnesium and copper, two minerals that are important for insulin sensitivity and cardiovascular health (2, 3). They're also high in potassium and vitamin C. Overall, they have a micronutrient content that compares favorably with other starchy root vegetables such as taro and cassava (4, 5, 6). Due to their very low fat content, potatoes contain virtually no omega-6, and thus do not contribute to an excess of these essential fatty acids.
Last edited by vonbraun; 11-30-2012 at 05:43 PM.
With that out of the way, we need to turn to the question of nitrogen balance, where nitrogen can only be supplied to the human body in the form of amine groups (NH3) from the amino acid components of protein. This is how protein status of individuals is scientifically and medically assessed. Deficiency is defined as excreting more nitrogen than one ingests ( negative nitrogen balance ) and the state we should strive for would be either equilibrium, or a positive nitrogen balance, where we respectively excrete the same amount, or less nitrogen, than we ingest.
Studies repeatedly show that while significantly calorically restricted, positive nitrogen balance is maintained in adults with an intake of 1.5 - 1.7g per kg of body mass. As I started my experiment I weighed near as makes no difference 85 kg which would then dictate a protein intake of roughly 130g if I were to apply the lower end of the recommended range. I was also ingesting 1500 kcal per day, 500 kcal less than my estimated BMR, which certainly qualifies as being significantly calorie restricted.
Now, to your numbers:
Using your data for Russet potatoes, 1500 kcal. would provide me with 40g of protein, thereby providing a meager 31% of the amount needed for nitrogen balance. If I try to hit my protein number, I would egregiously overshoot my calorie limit, requiring about 16 large Russets for an intake of 4700 kcal.
Potatoes make it impossible to hit the caloric and protein constraints simultaneously.
If I relax the caloric constraint, and focus only on the protein, I would still need to eat 4.3 kg., or close to 10 lbs. of potatoes, which is a stunningly large amount, and leads to my observation that potatoes are not "nutrient dense" by any reasonable definition of that phrase.
Faced with this reality, the only way to be calorically restricted and hit the protein requirements is to dial back the potatoes and add protein, which I did via the inclusion of egg whites and albacore tuna. I am unwilling to ignore the scientific literature on protein requirements.
I have only done a few days of tators, so I was not worried about protein, just like when I am fasting - I don't feel the need to supplement with protein for my muscles (not talking about restricting protein for autophagy) I am doing one week next week, and not sure how much I will worry about it then. Even not sure with 2 weeks how much I would worry but I might be more inclined to add BCAA supplements rather than other protein so maybe not to change the original PD too much. And I know from the beginning, yours was going to include other protein sources. So it is nice to know what your N=1 is from a potato+ diet.
I know you didnt have good results, but maybe you just werent fat enough? I think for me, that if I ate tators and tuna and eggs, I would lose weight. I don't know about all the other fancy numbers, but I am confident my fat would be going down. But I think it is only because I am fatter than you to begin with.
Just typing outloud. Only my thoughts and opinions.
65lbs gone and counting!!
Fat 2 Fit - One Woman's Journey
That said, I'd bet a few chicken livers or a couple oysters a day would make this diet pretty well-rounded in respect to micronutrients, although it will always be low in fat and protein for it to work.
When I do a 48 hour fast, I know that my protein metabolism will change, but this due largely to my hormonal profile changing. The seminal paper that started me down this road was one where males with normal BMIs fasting over 48 hours experienced 5 fold increases in their circulating growth hormone levels. Growth hormone promotes 1) retention of protein, and 2) fat mobilization. Assuming, then, that I am not some aberrant freak, but that I substantially resemble the study participants, I should benefit from the observed protein sparing effect as well.
To your point, though, this doesn't work the same in obese subjects. In those cases, the growth hormone release is blunted. But, this is actually expected, because in obese subject, the adipose cells are distended and leaking which is a characteristic of metabolic syndrome: high triglyceride levels in the plasma. Moreover, in terms of muscle mass, obese subjects definitely have more muscle simply because there is more to them to move around. Accordingly, locomotive muscles will exhibit disproportionate growth ... meaning large well developed lower body musculature. All of this means that in the obese subjects, there is no immediate need for the protein sparing and fat mobilization effects of growth hormone, but as these subject lean out, the GH response correspondingly comes into play.