Concerning whether sweet potatoes are superior to almonds:
1. Even thought the ratio of Vitmain E to PUFAs is 5 times better in a sweet potato than in almonds, the bioavailiability of of the Vitamin E in the almonds should be at least 5 times better than the sweet potato. The Vitamin E in the almonds should be very well absorbed as it is a whole food item, as is the sweet potato, but has over 50 times as much fat, which assists the absorption of this fat soluble vitamin. Not sure about the relative absorbability of the PUFAs.
There is actually no evidence for this and it is a misunderstanding of the physiology and biochemistry of Vit E digestion. In addition, the FAO/WHO report, which is the standard, disagrees with these statements.
What they do say...Absorption of vitamin E from the intestine depends on adequate pancreatic function, biliary secretion, and micelle formation. Conditions for absorption are like those for dietary lipid, that is, efficient emulsification, solubilisation within mixed bile salt micelles, uptake by enterocytes, and secretion into the circulation via the lymphatic system (6). Emulsification takes place initially in the stomach and then in the small intestine in the presence of pancreatic and biliary secretions. The resulting mixed micelle aggregates the vitamin E molecules, solubilises the vitamin E, and then transports it to the brush border membrane of the enterocyte probably by passive diffusion. Within the enterocyte, tocopherol is incorporated into chylomicrons and secreted into the intracellular space and lymphatic system and subsequently into the blood stream..
2. While it's true almonds provide 1.3 grams of saturated fat, it's not clear that negligible addition of saturated fat would increase disease risk. Sweet potatoes would have a far larger impact on blood glucose and possibly insulin, which increasing numbers of researchers (not just Atkins types) recognise as important in health.
I appreciate your speculations, but again, there is no evidence for this. In fact, populations that get about 60-90% of their calories from starches like sweet potatoes do not have higher rates of diabetes, metabolic syndrome or heart disease..
The saturated fat may matter depending on the amount in the rest of the diet and the amount of nuts/seeds added. I already showed this in the Going Nuts thread. In regard to saturated fat, we do know this, less is better, no exception.
3. I don't think it's fair to look at the overall vitamin and mineral content of any particular food item, but rather too look at the overall diet. There are many other foods on your approved list that almonds beat, but I wouldn't say that makes tham better. Same with omega 3:6 ratios.
Diets are made up of foods. It is impossible to have a healthy diet, with too many unhealthy foods. Looking at overall health/quality of individual foods is the best way to make a great overall healthy high quality diet. Of course, in the end, we want both. High quality foods and high quality diet.
If you are familiar with my posts/thread, then you know i am not advocating anything near "all or none" but that is not the point of this discussion.
Also, I don't know what list of approved foods of mine you are talking about, but yes, Almonds would be on it, but they would not be one of the overall highest quality foods or one I would be pushing and if included, my recommendation would be to limit all nuts/seeds/avocados, to nor more than 1-2 servings a day. I would not have the same limit on sweet potatoes.
4. I don't think caloric density is a very meaningful number for me. If a sweet potato has 160 calories, and an ounce of nuts has 160 calories, for me, that's all that matters..
You may want to consider it. The WCRF/AICR, the WHO, the FAO, the CDC, the USDA are all focusing on calorie density now because it turns out, that may be one of the bigger issues in our civilized diets.
True, an ounce may be 160 calories, but few, if any, can eat only an ounce. And, that is not by accident. Nuts/seeds were very rare in nature.
Almost 70% of American are overweight and almost 35% are obese and the numbers are getting worse even in children. FOr the first time in recorded history, life expectancy for children may be going down and is already for adult women in part of the country.
Calorie density may be the key to understanding why, and to understanding the solution.
So maybe almonds and sweet potatoes are about even health wise. And since you allow 1 to 2 oz of nuts, one certainly can have both..
There is room for both, however, as I showed, as does ETL, nutritiondata and CRON, the sweet potato, on virtually every known measure is a far superior food. I would have no objection to someone saying they wanted to make sweet potatoes their main source of calories. I would have a great concern if they told me that about almonds
The problem is that it's hard to stay within your guidelines if one is eating 2 ounces of nuts each day. If someone only ate two things in a day, 326 calories (2 oz) worth of almonds and 1670 calories of sweet potatoes, that's 14% fat. What's more, if you begin substituting all but 300 calories of sweet potatoes for a wider range of food, such as oatmeal, blueberries, kale, etc, the number goes above 15%. Now we're in Fuhrman country.
continued on next post...
Again, I do not know where you get your numbers. I use the USDA SR 20 Database and the CRON-O-Meter.
The sweet potato diet in the Going Nuts thread had 1 oz of nuts in it and it was 8% fat. Add in another oz and it was 12% fat.