{"id":521,"date":"2016-09-16T07:18:27","date_gmt":"2016-09-16T07:18:27","guid":{"rendered":"http:\/\/joshmitteldorf.peachpuff-wolverine-566518.hostingersite.com\/?p=521"},"modified":"2016-09-16T07:18:27","modified_gmt":"2016-09-16T07:18:27","slug":"nutritional-geometry-2-carb-restriction","status":"publish","type":"post","link":"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/","title":{"rendered":"Nutritional Geometry 2: Carb Restriction"},"content":{"rendered":"<p><a href=\"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/05\/nutritional-geometry\/\"><i>Last week<\/i><\/a><i>\u2019s focus was the evidence in favor of a low-protein diet. \u00a0In this context, high-carb diets came out on top. \u00a0But there is also evidence that for the average denizen of the developed world who does not restrict protein, there are dangers in a diet based on staple carbohydrates, especially sugars and simple starches that pass quickly from the stomach to raise blood sugar.<\/i><\/p>\n<p>Beginning in the 1970s, health literature convinced Americans to avoid fatty foods, and the processed food industry was eager to oblige, advertising \u201clow fat\u201d, while adding more sugar to make foods tasty, and taking advantage of a new, efficient chemical process that made high-fructose corn syrup cheaper than sugar. \u00a0But as we substituted carbs for fat, we became obese and diabetic. \u00a0<a href=\"http:\/\/www.mayoclinic.org\/diseases-conditions\/metabolic-syndrome\/home\/ovc-20197517\">Metabolic syndrome<\/a> and <a href=\"http:\/\/www.mayoclinic.org\/diseases-conditions\/type-2-diabetes\/home\/ovc-20169860\">Type 2 diabetes<\/a> were new terms added to the medical lexicon to describe what was ailing us. \u00a0<a href=\"http:\/\/science.sciencemag.org\/content\/291\/5513\/2536\">Gary Taubes<\/a> was first to hypothesize a causal relationship: \u00a0Our high-carb diet was leading to insulin resistance (which promotes weight gain) and weight gain (which promotes insulin resistance)\u2014a vicious cycle that he first wrote about in the 1990s.<\/p>\n<ul>\n<li style=\"font-weight: 400\">Diets that are high in fat, low in carbs, are an effective way to lose weight, at least in the short term. \u00a0<a href=\"http:\/\/www.dietsinreview.com\/diets\/the-calories-dont-count\/\">Herman Taller<\/a>, <a href=\"http:\/\/www.atkins.com\">Robert Atkins<\/a>, and <a href=\"http:\/\/www.zonediet.com\/about-us\/dr-sears\/\">Barry Sears<\/a> taught this truth to three successive generations of Americans.<\/li>\n<li style=\"font-weight: 400\">In animal experiments, insulin and its cousin IGF-1 are the hormones that mediate the connection between more food and shorter life.<\/li>\n<li style=\"font-weight: 400\"><a href=\"http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0047637409001055\">Blood sugar levels rise with age<\/a>, and in people with genes for exceptional longevity, the <a href=\"http:\/\/link.springer.com\/article\/10.1007\/s10522-009-9243-1\">rise happens more slowly<\/a>. \u00a0Blood sugar levels are a <a href=\"http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0047637409001055\">risk factor for mortality<\/a>. \u00a0So how much of a stretch is it, really, to say that the rise in blood sugar with age contributes to risk for the diseases of old age?<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-522 alignnone\" src=\"https:\/\/scienceblog.com\/wp-content\/uploads\/sites\/2\/2016\/09\/fasting-blood-sugar-vs-age_Yashin09.png\" alt=\"fasting-blood-sugar-vs-age_yashin09\" width=\"617\" height=\"503\" srcset=\"https:\/\/scienceblog.com\/joshmitteldorf\/wp-content\/uploads\/sites\/2\/2016\/09\/fasting-blood-sugar-vs-age_Yashin09.png 617w, https:\/\/scienceblog.com\/joshmitteldorf\/wp-content\/uploads\/sites\/2\/2016\/09\/fasting-blood-sugar-vs-age_Yashin09-300x245.png 300w, https:\/\/scienceblog.com\/joshmitteldorf\/wp-content\/uploads\/sites\/2\/2016\/09\/fasting-blood-sugar-vs-age_Yashin09-200x163.png 200w, https:\/\/scienceblog.com\/joshmitteldorf\/wp-content\/uploads\/sites\/2\/2016\/09\/fasting-blood-sugar-vs-age_Yashin09-368x300.png 368w\" sizes=\"auto, (max-width: 617px) 100vw, 617px\" \/><\/p>\n<p>The case against carbohydrates comes right out of mainstream practice for diabetes, but it has also been <a href=\"http:\/\/www.theatlantic.com\/health\/archive\/2013\/12\/this-is-your-brain-on-gluten\/282550\/\">treated as a fringe fad<\/a> when David Perlmutter stretched the case to make a point in a series of bestselling books. \u00a0In <a href=\"http:\/\/www.drperlmutter.com\/about\/grain-brain-by-david-perlmutter\/\">Grain Brain<\/a>, Perlmutter pounds home the association between high blood sugar and all the diseases of old age, but most especially dementia. \u00a0(Vascular dementia to a greater extent than Alzheimer\u2019s disease.)<\/p>\n<p>The combination of biochemistry with population data associating carb intake with metabolic syndrome has convinced many people that a carbohydrate-based diet is a hazzard. \u00a0But it\u2019s a difficult case to prove, because humans don\u2019t take well to living in cages, and because epidemiological studies of human aging require decades. \u00a0In reading this week, I\u2019ve discovered just how contentious is the whole subject of low-carb vs low-fat diets. Many such deeply divisive questions about health can be traced to corporate interests on one side, but this one may be academic, with ambiguous data, no long-term results, and different individual responses that are seen through different theoretical lenses.<\/p>\n<p>Although bottom-line questions about mortality and life expectancy may be difficult to address in human studies, we might hope for an answer to the question: Do people whose diets have a lower glycemic index have a lower risk of metabolic syndrome? \u00a0The best study I\u2019ve been able to find on this question [<a href=\"http:\/\/link.springer.com\/article\/10.1007\/s10522-009-9243-1\">2004<\/a>] associates insulin resistance with dietary factors in 2,800 sons and daughters of the original Framingham heart study.<\/p>\n<blockquote><p>After adjustment for potential confounding variables, intakes of total dietary fiber, cereal fiber, fruit fiber, and whole grains were inversely associated, whereas glycemic index and glycemic load were positively associated with [insulin resistance]. The prevalence of metabolic syndrome was significantly lower among those in the highest quintile of cereal fiber and whole-grain intakes relative to those in the lowest quintile category after adjustment for confounding lifestyle and dietary factors. Conversely, the prevalence of metabolic syndrome was significantly higher among individuals in the highest relative to the lowest quintile category of glycemic index.<\/p><\/blockquote>\n<p>Fruits and whole grains were found to provide protection against insulin resistance, despite the fact that they are primary carb sources. \u00a0Presumably, it is only sugar and simple carbs (white flour, rice, potatoes) that add to risk of insulin resistance.<\/p>\n<p>A South African doctor <a href=\"http:\/\/www.scielo.org.za\/scielo.php?pid=S0256-95742013001100013&amp;script=sci_arttext&amp;tlng=en\">collected stories<\/a> from patients who, by and large, were very satisfied with the results of switching to a low-carb, high-fat diet. Almost all lost weight. \u00a0Some claimed that their diabetes was \u201ccured\u201d.<\/p>\n<p>In <a href=\"http:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/oby.21331\/full\">this study<\/a>, people lost weight on a six-month program of either restricted fat or restricted carbs. \u00a0But people who were already insulin-resistant did a little better on the low carb diet, while those who still retained insulin sensitivity lost more on the low fat diet.<\/p>\n<p><a href=\"http:\/\/www.nejm.org\/doi\/full\/10.1056\/NEJMoa022637#t=article\">This study<\/a> put obese subjects with metabolic syndrome on either a low-fat or low-carb diet for six months. \u00a0Both groups lost weight and gained insulin sensitivity, on average. \u00a0The low-carb group lost more weight and gained more insulin sensitivity. \u00a0However, there was a lot of variation within the groups.<\/p>\n<blockquote><p>Insulin resistance is associated with diabetes and heart disease, both independently and as part of metabolic syndrome. Exercise has a strong beneficial effect and obesity a strong adverse effect. The balance of evidence suggests that a high-fat diet is likely to reduce insulin sensitivity but the effects of dietary carbohydrates are more controversial. Extensive studies in animals showed a detrimental effect of diets very high in fructose or sucrose, particularly in association with induction of hypertriglyceridemia. The more limited studies in humans had conflicting results, partly because of heterogeneity of design. Certain groups of subjects may be more sensitive to adverse effects of high intakes of dietary sucrose or fructose. <em>[<a href=\"http:\/\/ajcn.nutrition.org\/content\/66\/5\/1072.short\">ref<\/a>]<\/em><\/p><\/blockquote>\n<p>In other words, \u201cThere is conflicting evidence concerning the influence of total carbohydrate intake on insulin sensitivity.\u201d<\/p>\n<p>Two NIH studies [<a href=\"http:\/\/www.cell.com\/cell-metabolism\/pdf\/S1550-4131(15)00350-2.pdf\">one<\/a>, <a href=\"http:\/\/ajcn.nutrition.org\/content\/104\/2\/324.short\">two<\/a>] by Kevin Hall just this year compared short-term effects on metabolism from carb and fat restriction. \u00a0They put people in metabolic chambers to measure CO2 and H2O in their respiration, in order to calculate how much fat was being burned. \u00a0Hall claims that the results disprove the insulin theory of weight loss. \u00a0But to me the results seem puzzling and inconclusive. \u00a0They claim to calculate that the short-term weight loss from carb restriction is loss of muscle, not fat. \u00a0This is disturbing, if true. \u00a0The metabolic calculations are based on isotope labeling and other sophisticated technologies. \u00a0I trust the chemistry, but I tend to skepticism based on the fact that once in the body, labeled water gets mixed to an unknown extent with ubiquitous body water. \u00a0Short-term studies with sophisticated metabolomic measurements might tell us a good deal about the body\u2019s biochemistry, but still leave us wondering about long-term accommodations of hormonal balance, energy metabolism, and gut biota.<\/p>\n<p>Past positive results from low-carb diets, Hall says, are probably about \u201ccompliance\u201d and not metabolism. \u00a0\u201cCompliance\u201d is our ability to stick with a diet, and, IMHO, this should not be separated out as some kind of soft, psychological confounder. \u00a0It may well be that the whole advantage of a high fat diet is that those people for whom it works\u2014not everyone\u2014feel less hunger and more sustained energy, and that may well be linked to insulin cycling.<\/p>\n<p>What can we conclude but that we\u2019re each on our own, and we have to find the diet that works best for us as individuals? \u00a0And that that our dietary needs may change with age, so repeating the self-experimentation at least once a decade is helpful. \u00a0In experimenting on yourself, keeping weight off is probably as good a measure as any of how well your body is responding.<br \/>\n<b>Glycemic index and glycemic load<\/b><\/p>\n<p><b><i>Glycemic index<\/i><\/b> is about how quickly the carbohydrates in a particular food enter the bloodstream. \u00a0<b><i>Glycemic load<\/i><\/b> also takes into account how much carbohydrate the food contains, and also a guess at portion size. \u00a0<a href=\"http:\/\/www.health.harvard.edu\/diseases-and-conditions\/glycemic_index_and_glycemic_load_for_100_foods\">Here\u2019s a chart<\/a> from Harvard Med School with glycemic index and glycemic loads for 100 \u201ccommon foods\u201d (some more common than others). \u00a0Much of the chart is predictable\u2014cakes and sodas look bad, beans and nuts look good. \u00a0There are a few good surprises, and a few bad ones. \u00a0(Note that the GL listed for oranges =45 is almost certainly a mistake. \u00a0It should be 5 or 6.)<\/p>\n<table>\n<tbody>\n<tr>\n<td colspan=\"2\"><b>Good Surprises \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0GL<\/b><\/td>\n<td><\/td>\n<td colspan=\"2\"><b>Bad Surprises \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0GL<\/b><\/td>\n<\/tr>\n<tr>\n<td>Premium Ice Cream<\/td>\n<td>3<\/td>\n<td><\/td>\n<td>Cornflakes<\/td>\n<td>20<\/td>\n<\/tr>\n<tr>\n<td>Watermelon<\/td>\n<td>4<\/td>\n<td><\/td>\n<td>Ocean Spray Cranberry Juice<\/td>\n<td>24`<\/td>\n<\/tr>\n<tr>\n<td>Apple<\/td>\n<td>4<\/td>\n<td><\/td>\n<td>Pasta<\/td>\n<td>26<\/td>\n<\/tr>\n<tr>\n<td>Peanut M&amp;Ms<\/td>\n<td>7<\/td>\n<td><\/td>\n<td>Raisins<\/td>\n<td>28<\/td>\n<\/tr>\n<tr>\n<td>Whole Wheat bread<\/td>\n<td>8<\/td>\n<td><\/td>\n<td>Baked potato<\/td>\n<td>33<\/td>\n<\/tr>\n<tr>\n<td>Regular ice cream<\/td>\n<td>9<\/td>\n<td><\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The ranking by glycemic load is appropriate if you are trying to minimize total insulin burden. \u00a0But if you are aiming for a low-protein, high-carb diet as described last week, then you are interested in glycemic index (because you want high-carb foods that don\u2019t trigger insulin release). \u00a0The catch (for protein restricters) is that most foods with low GI are protein sources. \u00a0Which foods offer a combination of low protein and high carb without the insulin trigger? \u00a0Grapefruit stands out, apples, pears and other fruits will be preferred carb sources. \u00a0Some kinds of brown rice are more equal than others, while potatoes will be avoided because of too high a GI, while whole wheat and corn will be taken in moderation because they have too much protein.<\/p>\n<p>&nbsp;<\/p>\n<p><b>Fructose, Glucose, Sucrose<\/b><\/p>\n<p>So lotsa fruit seems to be the answer&#8230;until we introduce one more wrinkle. \u00a0Fruit contains fructose, and there is a school of thought that says fructose is much worse for you than glucose.<\/p>\n<p>There are two simple 6-carbon sugars, fructose and glucose, and table sugar=sucrose is a loose binding of one fructose with one glucose.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-large\" src=\"http:\/\/joelbergerdc.com\/wp-content\/uploads\/2013\/07\/GlucoseFructose.jpg\" alt=\"\" width=\"1200\" height=\"580\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-large\" src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/b\/b3\/Sucrose-inkscape.svg\/1280px-Sucrose-inkscape.svg.png\" alt=\"\" width=\"1280\" height=\"605\" \/><\/p>\n<p>Fructose and glucose are both sweet, and they\u2019re often found together in fruits. \u00a0Apples and pears have a lot more fructose than glucose, while bananas, peaches and sweet potatoes have a little more glucose than fructose. \u00a0Honey has more fructose than table sugar.<\/p>\n<p>Starch is a polymer of glucose. \u00a0It is quickly broken down (beginning in the mouth) into glucose molecules, so starchy foods have a high glycemic index. \u00a0But starch is all glucose, no fructose.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-524 aligncenter\" src=\"https:\/\/scienceblog.com\/wp-content\/uploads\/sites\/2\/2016\/09\/fructose-glucose.png\" alt=\"fructose-glucose\" width=\"941\" height=\"410\" srcset=\"https:\/\/scienceblog.com\/joshmitteldorf\/wp-content\/uploads\/sites\/2\/2016\/09\/fructose-glucose.png 941w, https:\/\/scienceblog.com\/joshmitteldorf\/wp-content\/uploads\/sites\/2\/2016\/09\/fructose-glucose-300x131.png 300w, https:\/\/scienceblog.com\/joshmitteldorf\/wp-content\/uploads\/sites\/2\/2016\/09\/fructose-glucose-768x335.png 768w, https:\/\/scienceblog.com\/joshmitteldorf\/wp-content\/uploads\/sites\/2\/2016\/09\/fructose-glucose-200x87.png 200w, https:\/\/scienceblog.com\/joshmitteldorf\/wp-content\/uploads\/sites\/2\/2016\/09\/fructose-glucose-500x218.png 500w\" sizes=\"auto, (max-width: 941px) 100vw, 941px\" \/><\/p>\n<p>Glucose and fructose may be chemical cousins, but the body treats them quite differently in the short term.<\/p>\n<ul>\n<li style=\"font-weight: 400\">Glucose is fuel, usable right away. \u00a0When you eat enough for your activity level, glucose is absorbed right into the blood, and it is consumed promptly. \u00a0When you eat more glucose than you can burn, insulin is secreted, signaling the liver to remove some glucose and turn it to glycogen. \u00a0The liver stores about a day\u2019s supply of glycogen to be drawn on as necessary, and glucose in excess of that is turned to triglycerides, a form convenient for storing energy in fat cells.<\/li>\n<li style=\"font-weight: 400\">Fructose is also absorbed promptly from the stomach into the bloodstream, but it is removed immediately by the liver, turned directly to triglycerides. \u00a0No insulin is involved.<\/li>\n<\/ul>\n<p>The short-term metabolism of fructose and glucose is well characterized, but you and I are interested in the long-term consequences of eating fruits high in fructose compared to starches which are quickly metabolized to glucose. \u00a0This turns out to be a controversial topic.<\/p>\n<p>In recent years, <a href=\"https:\/\/www.theguardian.com\/commentisfree\/2013\/oct\/21\/fructose-poison-sugar-industry-pseudoscience\">Robert Lustig<\/a> and <a href=\"http:\/\/livinlavidalowcarb.com\/blog\/excessive-fructose-intake-not-starch-leads-to-metabolic-syndrome-author-contends\/2748\">Richard Johnson<\/a> have argued that foods with more fructose than glucose lead quickly to insulin resistance. \u00a0They blame soaring rates of obesity and metabolic syndrome=type 2 diabetes on the invention of a process for producing sugar from corn starch that is cheaper than cane sugar. \u00a0The \u201chigh-fructose corn syrup\u201d that results happens to be 55% fructose.<\/p>\n<blockquote><p>Yes, fructose has a low glycaemic index of 19, because it doesn&#8217;t increase blood glucose. It&#8217;s fructose, for goodness sake. It increases blood fructose, which is way worse. Fructose causes seven times as much cell damage as does glucose, because it binds to cellular proteins seven times faster; and it releases 100 times the number of oxygen radicals (such as hydrogen peroxide, which kills everything in sight). Indeed, a 20oz soda results in a serum fructose concentration of six micromolar, enough to do major arterial and pancreatic damage. Glycaemic index is a canard; and fructose makes it so. Because fructose\u2019s poisonous effects have nothing to do with glycaemic index; they are beyond glycaemic index. [<a href=\"https:\/\/www.theguardian.com\/commentisfree\/2013\/oct\/21\/fructose-poison-sugar-industry-pseudoscience\">Lustig writing in The Guardian<\/a>]<\/p><\/blockquote>\n<p>I\u2019m not so impressed with the \u201cseven times faster\u201d, because fructose doesn\u2019t remain long in the bloodstream, and I\u2019m not so concerned about free radicals because (<a href=\"https:\/\/scienceblog.com\/joshmitteldorf\/2014\/02\/17\/anti-oxidants-can-nullify-the-benefits-of-exercise\/\">as I\u2019ve written<\/a>) they are as likely to increase our life expectancy as to decrease it. \u00a0Lustig also writes that because fructose tastes so good and bypasses insulin and blood sugar, it undermines the satiety response and leads to compulsive eating. \u00a0But the most complelling claim here is about the loss of insulin sensitivity, which I regard as a hallmark of aging. \u00a0Is fructose really worse for insulin resistance than glucose? \u00a0Lustig says YES, and his theory is articulated <a href=\"http:\/\/advances.nutrition.org\/content\/4\/2\/226.full\">here<\/a>. \u00a0Lustig makes his case by reasoning about biochemistry in the liver. \u00a0But what about real evidence in real people? \u00a0In short-term studies, substitution of fructose for glucose in the diet shows no sign of increasing insulin resistance; on the other hand, there is a well-known correlation between consumption of high-fructose corn syrup with metabolic disease.<\/p>\n<p>What Lustig comes to beneath the headlines is, \u201cthe dose makes the poison\u201d; and I think this is a healthy attitude for all of us. \u00a0Drinking sugared beverages and eating (more than occasionally) foods sweetened with high-fructose corn syrup damages insulin sensitivity. \u00a0At the other end, eating a few pieces of fruit during the day can be part of many diet plans that work well for health and longevity. \u00a0Those are the easy cases. \u00a0In between we have the more difficult case of the semi-fructarian. \u00a0That would be me. \u00a0I get most of my carbs from fruit, and I avoid starch (rice, potatoes, bread, pasta). \u00a0I maintain weight with exercise and portion control, I eat leafy greens every day and I get a ton of fiber, and though my protein intake is high compared to last week\u2019s ideal (~60g\/day), it\u2019s all vegetable protein. \u00a0Would I be better off if I backed off from my fruit consumption and substituted whole wheat bread and other complex carbohydrates? \u00a0It\u2019s an experiment that I might try next winter\u2014but not in September when every kind of delicious fruit is fresh and abundant.<\/p>\n<p>In any case, there is a consensus view that moderate fructose is part of a healthy diet, and that excessive fructose exacerbates the ill effects of a sugary diet [<a href=\"http:\/\/ajcn.nutrition.org\/content\/76\/5\/911.full\">ref<\/a>, <a href=\"http:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC2682989\/\">ref<\/a>, <a href=\"http:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC4161399\/\">ref<\/a>, <a href=\"http:\/\/www.ncbi.nlm.nih.gov\/pubmed\/23872500\">ref<\/a>, <a href=\"http:\/\/care.diabetesjournals.org\/content\/35\/7\/1611\">ref<\/a>, <a href=\"http:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/oby.21371\/full\">ref<\/a>, <a href=\"http:\/\/www.ncbi.nlm.nih.gov\/pubmed\/16820733\">ref<\/a>]. \u00a0After reading all these articles (well&#8230;reading all the abstracts and some of the content underneath), I\u2019m not convinced one way or the other about fruits (glucose+fructose) vs grains (glucose only, from starch).<\/p>\n<p>&nbsp;<\/p>\n<p><b>Insulin resistance is tied to high blood sugar<\/b><\/p>\n<p>Metabolic syndrome, including the \u201cnormal\u201d version that comes with aging, is characterized by failure to respond to insulin, leading to both higher insulin levels and higher blood sugar. \u00a0Is it the higher insulin level or the higher blood sugar that is responsible for\u00a0the damage? \u00a0YES.<\/p>\n<p>Insulin signaling speeds up the rate of aging. \u00a0Sugar in the blood reacts with proteins to create cross links (<a href=\"https:\/\/en.wikipedia.org\/wiki\/Glycation\">glycation<\/a>) that prevents the protein from folding properly. \u00a0(Fructose is more prone to this reaction than glucose, but fructose does not stay in the blood so long.) \u00a0Type I diabetics have no insulin, and if their insulin injections are not carefully regulated, they are at risk for blindness and nerve damage in the extremities, both from high blood sugar. \u00a0So, with metabolic syndrome, both the insulin levels and high blood sugar pose risks. \u00a0The proper medical terminology for this situation is \u201c<a href=\"http:\/\/www.urbandictionary.com\/define.php?term=double%20whammy\">double whammy<\/a>\u201d.<\/p>\n<p>So both high insulin and high blood sugar are bad for us. \u00a0With the separation of fructose from glucose, we have the possibility of coupling lower insulin levels with higher blood sugar. Is the tradeoff worthwhile? <a href=\"http:\/\/www.ncbi.nlm.nih.gov\/pubmed\/16820733\">Is fructose the optimal low glycemic index sweetener?<\/a><\/p>\n<p><strong>And in the end&#8230;<\/strong><\/p>\n<p>You have every right to ask where I\u2019m going to come down on these questions after a post that is longer and fuller of ambiguities than the usual. \u00a0I\u2019m going to disappoint you. It\u2019s clear to me<\/p>\n<ul>\n<li>that excessive sugar, both glucose and fructose, is bad for most everyone<\/li>\n<li>that high fiber is good in a lot of ways<\/li>\n<li>that different metabolisms respond differently to low-carb and low-fat diets.<\/li>\n<li>that weight control is a good way to tell if a diet is working for you<\/li>\n<\/ul>\n<p>It leaves me counseling personal experimentation, which is what I always say anyway.<\/p>\n<blockquote><p>There is a phenomenal amount of individual variability in energy expenditure, both resting and total. \u00a0 Measured across two weeks, one person had total EE \u00a0almost 800 cal\/day above their baseline while another had a EE almost 1200 cal\/day below baseline. \u00a0That\u2019s huge. \u00a0I imagine that the individual whose resting EE declined by almost 500 cal\/day will be having a tougher time maintaining his\/her weight loss than those lucky few who saw increases.\u00a0<i>[<a href=\"http:\/\/carbsanity.blogspot.com\/2012\/07\/what-we-really-learn-from-ebbeling-etal.html\">from a pro-carb blogger<\/a>]<\/i><\/p>\n<p>&nbsp;<\/p><\/blockquote>\n<p><b>A simple program for weight loss and life extension<\/b><\/p>\n<p>Before each time that you eat, do <a href=\"https:\/\/scienceblog.com\/joshmitteldorf\/2014\/02\/25\/one-minute-workouts\/\">1 to 2 minutes of exercise<\/a>, intense enough to leave you panting and drink a pint of water. \u00a0The result is to suppress the sugar and insulin spikes that follow a meal, and to burn more of the food energy, store less as fat.<\/p>\n<p style=\"text-align: center\"><strong>Next week, part 3: Specifics on the high-fat, ketogenic diet<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Last week\u2019s focus was the evidence in favor of a low-protein diet. \u00a0In this context, high-carb diets came out on top. \u00a0But there is also evidence that for the average denizen of the developed world who does not restrict protein, there are dangers in a diet based on staple carbohydrates, especially sugars and simple starches &#8230; <a title=\"Nutritional Geometry 2: Carb Restriction\" class=\"read-more\" href=\"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/\" aria-label=\"Read more about Nutritional Geometry 2: Carb Restriction\">Read more<\/a><\/p>\n","protected":false},"author":65,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[1],"tags":[],"class_list":["post-521","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.6 (Yoast SEO v27.6) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Nutritional Geometry 2: Carb Restriction - Josh Mitteldorf<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Nutritional Geometry 2: Carb Restriction\" \/>\n<meta property=\"og:description\" content=\"Last week\u2019s focus was the evidence in favor of a low-protein diet. \u00a0In this context, high-carb diets came out on top. \u00a0But there is also evidence that for the average denizen of the developed world who does not restrict protein, there are dangers in a diet based on staple carbohydrates, especially sugars and simple starches ... Read more\" \/>\n<meta property=\"og:url\" content=\"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/\" \/>\n<meta property=\"og:site_name\" content=\"Josh Mitteldorf\" \/>\n<meta property=\"article:published_time\" content=\"2016-09-16T07:18:27+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/scienceblog.com\/wp-content\/uploads\/sites\/2\/2016\/09\/fasting-blood-sugar-vs-age_Yashin09.png\" \/>\n<meta name=\"author\" content=\"Josh Mitteldorf\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Josh Mitteldorf\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"14 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/scienceblog.com\\\/joshmitteldorf\\\/2016\\\/09\\\/16\\\/nutritional-geometry-2-carb-restriction\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/scienceblog.com\\\/joshmitteldorf\\\/2016\\\/09\\\/16\\\/nutritional-geometry-2-carb-restriction\\\/\"},\"author\":{\"name\":\"Josh Mitteldorf\",\"@id\":\"https:\\\/\\\/scienceblog.com\\\/joshmitteldorf\\\/#\\\/schema\\\/person\\\/214c5d1dad9f15c48f03128d5cfccdb1\"},\"headline\":\"Nutritional Geometry 2: Carb Restriction\",\"datePublished\":\"2016-09-16T07:18:27+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/scienceblog.com\\\/joshmitteldorf\\\/2016\\\/09\\\/16\\\/nutritional-geometry-2-carb-restriction\\\/\"},\"wordCount\":2890,\"commentCount\":8,\"publisher\":{\"@id\":\"https:\\\/\\\/scienceblog.com\\\/joshmitteldorf\\\/#organization\"},\"image\":{\"@id\":\"https:\\\/\\\/scienceblog.com\\\/joshmitteldorf\\\/2016\\\/09\\\/16\\\/nutritional-geometry-2-carb-restriction\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/scienceblog.com\\\/wp-content\\\/uploads\\\/sites\\\/2\\\/2016\\\/09\\\/fasting-blood-sugar-vs-age_Yashin09.png\",\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/scienceblog.com\\\/joshmitteldorf\\\/2016\\\/09\\\/16\\\/nutritional-geometry-2-carb-restriction\\\/#respond\"]}],\"copyrightYear\":\"2016\",\"copyrightHolder\":{\"@id\":\"https:\\\/\\\/scienceblog.com\\\/#organization\"}},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/scienceblog.com\\\/joshmitteldorf\\\/2016\\\/09\\\/16\\\/nutritional-geometry-2-carb-restriction\\\/\",\"url\":\"https:\\\/\\\/scienceblog.com\\\/joshmitteldorf\\\/2016\\\/09\\\/16\\\/nutritional-geometry-2-carb-restriction\\\/\",\"name\":\"Nutritional Geometry 2: Carb Restriction - 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The surprising fact that our bodies are genetically programmed to age and to die offers an enormous opportunity for medical intervention. It may be that therapies to slow the progress of aging need not repair or regenerate anything, but only need to interfere with an existing program of self-destruction. Mitteldorf has taught a weekly yoga class for thirty years. He is an advocate for vigorous self care, including exercise, meditation and caloric restriction. After earning a PhD in astrophysicist, Mitteldorf moved to evolutionary biology as a primary field in 1996. He has taught at Harvard, Berkeley, Bryn Mawr, LaSalle and Temple University. He is presently affiliated with MIT as a visiting scholar. In private life, Mitteldorf is an advocate for election integrity as well as public health. He is an avid amateur musician, playing piano in chamber groups, French horn in community orchestras. His two daughters are among the first children adopted from China in the mid-1980s. Much to the surprise of evolutionary biologists, genetic experiments indicate that aging has been selected as an adaptation for its own sake. This poses a conundrum: the impact of aging on individual fitness is wholly negative, so aging must be regarded as a kind of evolutionary altruism. Unlike other forms of evolutionary altruism, aging offers benefits to the community that are weak, and not well focussed on near kin of the altruist. This makes the mechanism challenging to understand and to model. more at http:\\\/\\\/mathforum.org\\\/~josh\",\"sameAs\":[\"http:\\\/\\\/AgingAdvice.org\"],\"url\":\"https:\\\/\\\/scienceblog.com\\\/joshmitteldorf\\\/author\\\/joshmitteldorf\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Nutritional Geometry 2: Carb Restriction - Josh Mitteldorf","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/","og_locale":"en_US","og_type":"article","og_title":"Nutritional Geometry 2: Carb Restriction","og_description":"Last week\u2019s focus was the evidence in favor of a low-protein diet. \u00a0In this context, high-carb diets came out on top. \u00a0But there is also evidence that for the average denizen of the developed world who does not restrict protein, there are dangers in a diet based on staple carbohydrates, especially sugars and simple starches ... Read more","og_url":"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/","og_site_name":"Josh Mitteldorf","article_published_time":"2016-09-16T07:18:27+00:00","og_image":[{"url":"https:\/\/scienceblog.com\/wp-content\/uploads\/sites\/2\/2016\/09\/fasting-blood-sugar-vs-age_Yashin09.png","type":"","width":"","height":""}],"author":"Josh Mitteldorf","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Josh Mitteldorf","Est. reading time":"14 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/#article","isPartOf":{"@id":"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/"},"author":{"name":"Josh Mitteldorf","@id":"https:\/\/scienceblog.com\/joshmitteldorf\/#\/schema\/person\/214c5d1dad9f15c48f03128d5cfccdb1"},"headline":"Nutritional Geometry 2: Carb Restriction","datePublished":"2016-09-16T07:18:27+00:00","mainEntityOfPage":{"@id":"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/"},"wordCount":2890,"commentCount":8,"publisher":{"@id":"https:\/\/scienceblog.com\/joshmitteldorf\/#organization"},"image":{"@id":"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/#primaryimage"},"thumbnailUrl":"https:\/\/scienceblog.com\/wp-content\/uploads\/sites\/2\/2016\/09\/fasting-blood-sugar-vs-age_Yashin09.png","inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/#respond"]}],"copyrightYear":"2016","copyrightHolder":{"@id":"https:\/\/scienceblog.com\/#organization"}},{"@type":"WebPage","@id":"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/","url":"https:\/\/scienceblog.com\/joshmitteldorf\/2016\/09\/16\/nutritional-geometry-2-carb-restriction\/","name":"Nutritional Geometry 2: Carb Restriction - 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The surprising fact that our bodies are genetically programmed to age and to die offers an enormous opportunity for medical intervention. It may be that therapies to slow the progress of aging need not repair or regenerate anything, but only need to interfere with an existing program of self-destruction. Mitteldorf has taught a weekly yoga class for thirty years. He is an advocate for vigorous self care, including exercise, meditation and caloric restriction. After earning a PhD in astrophysicist, Mitteldorf moved to evolutionary biology as a primary field in 1996. He has taught at Harvard, Berkeley, Bryn Mawr, LaSalle and Temple University. He is presently affiliated with MIT as a visiting scholar. In private life, Mitteldorf is an advocate for election integrity as well as public health. He is an avid amateur musician, playing piano in chamber groups, French horn in community orchestras. His two daughters are among the first children adopted from China in the mid-1980s. Much to the surprise of evolutionary biologists, genetic experiments indicate that aging has been selected as an adaptation for its own sake. This poses a conundrum: the impact of aging on individual fitness is wholly negative, so aging must be regarded as a kind of evolutionary altruism. Unlike other forms of evolutionary altruism, aging offers benefits to the community that are weak, and not well focussed on near kin of the altruist. This makes the mechanism challenging to understand and to model. more at http:\/\/mathforum.org\/~josh","sameAs":["http:\/\/AgingAdvice.org"],"url":"https:\/\/scienceblog.com\/joshmitteldorf\/author\/joshmitteldorf\/"}]}},"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pgtN8h-8p","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/scienceblog.com\/joshmitteldorf\/wp-json\/wp\/v2\/posts\/521","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/scienceblog.com\/joshmitteldorf\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scienceblog.com\/joshmitteldorf\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scienceblog.com\/joshmitteldorf\/wp-json\/wp\/v2\/users\/65"}],"replies":[{"embeddable":true,"href":"https:\/\/scienceblog.com\/joshmitteldorf\/wp-json\/wp\/v2\/comments?post=521"}],"version-history":[{"count":0,"href":"https:\/\/scienceblog.com\/joshmitteldorf\/wp-json\/wp\/v2\/posts\/521\/revisions"}],"wp:attachment":[{"href":"https:\/\/scienceblog.com\/joshmitteldorf\/wp-json\/wp\/v2\/media?parent=521"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scienceblog.com\/joshmitteldorf\/wp-json\/wp\/v2\/categories?post=521"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scienceblog.com\/joshmitteldorf\/wp-json\/wp\/v2\/tags?post=521"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}