Carbohydrate and Fat Controversies: Part 2

In Carbohydrate and Fat Controversies: Part 1, I begun an examination of the argument over carbohydrate and fat intakes in the human diet, explaining that, contrary to popular argument, most extremist stances in this debate are incorrect. In Part 2, I want to continue addressing the issue by looking at both sides of the debate.

Examining Both Sides of the Debate

As noted, the usual argument goes that high-fat diets cause high-cholesterol, heart disease, cancer, obesity and the rest, as evidenced by the high incidence of those disease in modern diets (which are typically high in fat). But that’s a questionable conclusion to draw.

Modern diets are also high in carbohydrates (and mainly the highly refined, high GI, low-fiber stuff that the body often doesn’t handle well), low in fruits and vegetables, and generally contain the wrong types of fats (an excess of saturated and trans fats with insufficient amounts of healthy fats). Such an intake is typically coupled with inactivity, the folks eating them tend to be overweight/obese, smoking and alcohol play a role, etc. That is, there are a number of inter-related factors at work here.

Pinning the blame entirely on fat intake or expecting only a reduction in fat to fix the problem is disingenuous: there are a lot of variables at work here. Some research suggests that the entirety of the problem rests with excessive saturated fat intake with the other variables (activity, fruits and vegetables, etc.) playing a relatively minor role. It’s awfully hard to tease out all of the relationships when there are this many variables at play.

Similar comments can be made in terms of obesity. Fat is more calorically dense than carbohydrates and studies comparing high-fat (40%) to low-fat (25%) meals find that people tend to eat more in the higher fat conditions; this is usually referred to as passive over-consumption and leads to excess calorie intake. These studies have problems, mind you, but that’s beyond the scope of this article. The point does stand, though, that dietary fat is tasty (giving food mouth feel) and folks do tend to eat more of foods that taste good.

But while it’s common to blame obesity on high-fat diets, not all researchers agree. Some cultures have fairly high fat intakes but have no problems with obesity and researchers are starting to realize that fat isn’t the ONLY problem. Increasing intakes of refined carbohydrates (contributing large numbers of calories to the diet), decreasing activity, increasing portion sizes and other factors all contribute. You can’t dismiss an excessive fat intake as part of the obesity problem; it’s simply not the sole factor. I don’t want to get into a massive discussion of the carb versus fat debate in terms of caloric intake, preferring to focus on the health issues here.

The fact is that not all studies link a high fat intake to an increased risk of disease. For example, recent analyses of our ancestral diet (what we ate during 99.9% of our evolution) suggests a much higher fat intake and much lower daily carbohydrate intake. Exact numbers vary depending on what assumptions you use but carb intakes of 20-40% (most of which came from low GI, high fiber fruits and vegetables; grains were almost non-existent), fat intakes of 28-60% (which had a significantly different quality than our current diet), and protein intakes of 19-35% of total calories are the current best estimates.

Studies of extant hunter-gatherer societies show little incidence of any of the diseases of modern society and it’s thought that our evolutionary diet was NOT atherogenic (promoting heart disease) despite the high fat intake.

The reasons for this are many-fold, of course and that’s the key to keep in mind when you consider fat intakes and potential health problems. In our ancestral diet, fiber intakes were monstrous, averaging 100-150 grams per day. As well, despite the high fat intake, the source of that fat was far, far different than our modern intake. Much higher intakes of polyunsaturated and mono-unsaturated fats and far lower intakes of saturated fat were fairly typical. Activity levels were also much higher and folks generally stayed pretty lean. Alcohol intake was low or non-existent, as was smoking. Although our ancestors dealt with various stresses, they didn’t deal with the kinds of chronic stress that occurs in modern societies.

Related to this, studies of the Mediterranean diet have found few problems in terms of heart disease and all the rest despite a relatively high fat intake (40% of total calories). Although the reasons are, as always, multi-factorial some of the contributing factors are that the fat intake is primarily from mono-unsaturated sources (e.g. olive oil).

As well, a tremendous amount of fresh vegetables are typically consumed (with far less reliance on refined carbohydrates). Other factors such as activity, bodyweight, moderate alcohol intake and lowered stress levels probably play a role. Studies of the Alaskan Inuit show similar results, despite an extremely high-fat intake, heart disease is almost unheard of. This has typically been attributed to the high intake of fish oils but there may be genetic adaptations as well.

Of course, some studies on low-carbohydrates diets (which are typically high in fat) will show a big improvement in blood lipid levels; this is especially true for individuals with insulin resistance. I’d note that this effect primarily occurs when weight is lost; in studies of very low-carbohydrate diets where weight is gained, blood lipid levels often get much much worse.

Thus, whether or not you’re gaining or losing weight probably impacts on whether or not dietary fat is a health risk. I’d note that studies in cyclists find that high intakes of saturated fat don’t pose a health problem as long as the athletes are in calorie balance. As I mentioned above, activity (which will affect whether ingested dietary fat is stored or burned off) plays a big role here.

Studies in diabetics are finding that higher mono-unsaturated fat intakes (and lowered carbohydrate) intakes may be healthier than the converse. This, of course, only holds if calories are strictly monitored and controlled to avoid weight gain. When weight is gained, from nearly any dietary approach, blood sugar control in diabetics worsens.

Of course, there’s a flip side to the anti-fat dogma and reducing fat to extreme levels can cause its own set of problems. First and foremost, most people find extremely low-fat diets to be tasteless and this tends to limit adherence in the long-term (as I mentioned above, high-fat diets tend to be very tasty and people frequently eat too much).

And while caloric intake typically goes down in the short-term, folks frequently end up increasing caloric intake because they are hungry all the time. Dietary fat slows gastric emptying (keeping food in the gut longer) although some work suggests that this effect is lost with chronically high-fat diets. Extremely low-fat diets tend to leave people hungrier for this reason.

There is also evidence that the fat-soluble vitamin absorption may be impaired when fat intake is taken too low. And while total cholesterol typically decreases when fat intake is lowered, the decrease occurs in both the good (HDL) and bad (LDL) sub-fractions so overall health risk may not be improved. From a body recomposition or performance standpoint, some studies show a lowering of testosterone with very low fat diets.

There is another set of issues that crops up as well. Again, it relates to the simple fact that people have to eat something. In reducing fat intake, most people increase carbohydrate intake. Most researchers would say that this is just fine as long as the increase comes in the form of unrefined, high fiber, complex carbohydrates. I would say that most researchers need to get out of the lab and look at the real world for a while.

The simple fact is that the majority of people who reduce fat do NOT increase carbohydrate intake from unrefined, high-fiber, complex sources. This is especially apparent in the US (I can’t speak for other countries) where companies rapidly jumped on the ‘fat is bad’ bandwagon and brought tons of ‘low-fat’ high-carbohydrate sources that were highly refined to market.

Such foods may have as many, if not more, calories than the same higher-fat items. Even when they don’t, humans play a cute psychological game, tending to eat more of a given food when they are told it’s low or no-fat.

Recent studies are finding that, when carbs are increased from those sources, other problems show up. In addition to the changes in blood cholesterol I mentioned above (both the good and bad subfraction decrease), the increase in refined carbohydrate intake causes an increase in blood triglyceride levels and small LDL particles; both of which are independent risk factors for heart disease and all the rest. The chronically high insulin levels which commonly occur with such a diet cause other problems including insulin resistance and all of the issues that accompany it.

I should probably note, and this could certainly be an entirely separate article, that the new scapegoat for obesity and all of the health problems in the world is excessive carbohydrate intake, with a lot of the focus on insulin release. I don’t have space here to address that side of the argument, a future topic for another day.

Sufficed to say that while there is certainly an element of truth to this (in that excessive intakes of any nutrient, and that includes refined carbohydrates, is bad), it’s still true that simplistically arguing that ‘fat is good and carbs are bad’ is just as moronic as arguing that ‘carbs are good and fat is bad’. Again, it depends on the context.

Summing Up

Now, I want to make it very clear that I’m not trying to make this either a pro-fat or anti-carbohydrate article or trying to make a low-carbohydrate diet the default choice for anybody. My point is simply that the idea that ‘fat is bad’ and ‘carbs are good’ (or the opposite) is too simplistic to be meaningful.

Not all fat is bad and not all carbs are good. The source, the composition of the rest of the diet, the total amounts you’re eating of each, your activity level and other variables all factor in. Whether you’re talking about health risk or obesity, you can’t simply pin the blame on one factor or the other.

So, under conditions of high caloric intake, with a high intake of refined carbohydrates (meaning chronically high insulin levels), poor quality fat choices (too much saturated fat and/or too little unsaturated fats), little activity, minimal fruit and vegetable intake, etc. a high-fat intake is probably very detrimental from a health standpoint. Sadly, this describes a fairly typical diet in the modern world (especially the US).

In contrast, with reduced or even controlled caloric intake (such that bodyweight goes down or is maintained) and most of the fat coming from unsaturated sources (note: excessive polyunsaturated fats has its own set of problems), a high fruit and vegetable intake, reasonable activity levels, keeping body fat levels down, etc. higher fat intakes may be no problem at all. In some situations, an increased fat intake (again, from healthy sources within the context of activity and a high fruit and vegetable intake) may be beneficial compared to the alternatives (e.g. increasing carbohydrate intake).

Comments

comments

19 thoughts on “Carbohydrate and Fat Controversies: Part 2

  1. Hi Lyle,

    Are you familiar with the work of biochemist Roger J. Williams, PhD? If not, I recommend “Biochemical Individuality” and “Nutrition Against Disease.” I’m suggesting you read these books because, while very knowledgeable in many respects, you seem to view saturated fat as somewhat of a health hazard. After more than 30 years of studying nutrition, I see omega 6 oils as a major health hazard rather than saturated fats. Suggest you Google “omega 6 oils hazards” and “Peter Havel fructose.”

    Another issue is unabsorbed calories. Individuals are variously biochemically and physiologically equipped to absorb calories more or less efficiently. Average absorption is about 80 percent ranging down to 40 percent depending on soluble fiber intake. Suggest you Google “unabsorbed calories” or Calorie Excretion” for more info.

    I like your open-minded approach.

    Regards,
    David Brown
    Nutrition Education Project

  2. David

    I have read Biochemical Individuality. Beyond that, I’d suggest you reread my articles since you apparently missed my point. Or did you miss comments like:

    ‘Thus, whether or not you’re gaining or losing weight probably impacts on whether or not dietary fat is a health risk. I’d note that studies in cyclists find that high intakes of saturated fat don’t pose a health problem as long as the athletes are in calorie balance. As I mentioned above, activity (which will affect whether ingested dietary fat is stored or burned off) plays a big role here.”

    Whether saturated fat is positive, negative or neutral depends on a staggering number of factors including activity, the rest of the diet, whether they are eating more, less or as much as they need. Etc. All addressed in my articles in detail.

    Rather, you MIS-read my articles through your own filter. You ‘heard’ me say that saturated fat is unhealthy when I said no such thing.

    That’s why it’s a controversy.

    Saturated fat in the context of the modern diet (inactivity, high carb intake, obesity, inflammation) is distinctly unhealthy and the studies all support that. Saturated fat in the context of high activity, lots of vegetables, leanness) probably is no big deal and the studies support that too.

    Saying that it’s ‘healthy’ is as simplistically wrong as saying that it’s unhealthy.

    It DEPENDS on the context.

    As well, if you can show me a peer reviewed study showing caloric absorption as low as 40%, I’ve love to see it. Because it doesn’t exist. Soluble fiber has, at best, a small effect on caloric absorption.

    Excess w-6 can certainly be a problem although I’d point you to recent work suggesting that w-6 can have anti-inflammatory effects. It’s certainly not as cut and dry as the books you’re reading make it sound. I’d suggest you spend more time on Medline and less time reading fringe dietary advice to become whatever is it you want to become.

    Lyle

    ***
    Too much linoleic acid promotes inflammation-doesn’t it?

    Fritsche KL.

    Prostaglandins Leukot Essent Fatty Acids. 2008 Nov 4. [Epub ahead of print]

  3. This is a poorly written article. Our ancestral intake of fat was not saturated? Organs were eaten first, followed by the most fatty cuts of meat. Lean meat has no place in the human diet. Fat is important, especially saturated fat. As soon as someone puts forth the argument that people consume more calories when they eat calorically dense foods such as fat, they are focusing on the wrong issue. Hunger is not a function of stomach contents, it is a function of the energy needs on a cellular level. Fat has more calories per gram than protein and carbs, and that is why humans thrive on higher fat diets. Efficiency is an evolutionary advantage that has allowed us as humans to have large brains and strong muscles. Eat animal fat, not sugar and starch, and your body will be in prime condition.

  4. You sure about that

    ***
    Eur J Clin Nutr. 2002 Mar;56 Suppl 1:S42-52.Click here to read Links
    The paradoxical nature of hunter-gatherer diets: meat-based, yet non-atherogenic.
    Cordain L, Eaton SB, Miller JB, Mann N, Hill K.

    Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado, USA. cordain@cahs.colostate.edu

    OBJECTIVE: Field studies of twentieth century hunter-gathers (HG) showed them to be generally free of the signs and symptoms of cardiovascular disease (CVD). Consequently, the characterization of HG diets may have important implications in designing therapeutic diets that reduce the risk for CVD in Westernized societies. Based upon limited ethnographic data (n=58 HG societies) and a single quantitative dietary study, it has been commonly inferred that gathered plant foods provided the dominant energy source in HG diets. METHOD AND RESULTS: In this review we have analyzed the 13 known quantitative dietary studies of HG and demonstrate that animal food actually provided the dominant (65%) energy source, while gathered plant foods comprised the remainder (35%). This data is consistent with a more recent, comprehensive review of the entire ethnographic data (n=229 HG societies) that showed the mean subsistence dependence upon gathered plant foods was 32%, whereas it was 68% for animal foods. Other evidence, including isotopic analyses of Paleolithic hominid collagen tissue, reductions in hominid gut size, low activity levels of certain enzymes, and optimal foraging data all point toward a long history of meat-based diets in our species. Because increasing meat consumption in Western diets is frequently associated with increased risk for CVD mortality, it is seemingly paradoxical that HG societies, who consume the majority of their energy from animal food, have been shown to be relatively free of the signs and symptoms of CVD. CONCLUSION: The high reliance upon animal-based foods would not have necessarily elicited unfavorable blood lipid profiles because of the hypolipidemic effects of high dietary protein (19-35% energy) and the relatively low level of dietary carbohydrate (22-40% energy). Although fat intake (28-58% energy) would have been similar to or higher than that found in Western diets, it is likely that important qualitative differences in fat intake, including relatively high levels of MUFA and PUFA and a lower omega-6/omega-3 fatty acid ratio, would have served to inhibit the development of CVD. Other dietary characteristics including high intakes of antioxidants, fiber, vitamins and phytochemicals along with a low salt intake may have operated synergistically with lifestyle characteristics (more exercise, less stress and no smoking) to further deter the development of CVD.

    ***
    Mayo Clin Proc. 2004 Jan;79(1):101-8.Click here to read Links

    Comment in:
    Mayo Clin Proc. 2004 May;79(5):703; author reply 703-4, 707.

    Cardiovascular disease resulting from a diet and lifestyle at odds with our Paleolithic genome: how to become a 21st-century hunter-gatherer.
    O’Keefe JH Jr, Cordain L.

    Mid America Heart Institute, Cardiovascular Consultants, Kansas City, MO 64111, USA. jhokeefe@cc-pc.com

    Our genetic make-up, shaped through millions of years of evolution, determines our nutritional and activity needs. Although the human genome has remained primarily unchanged since the agricultural revolution 10,000 years ago, our diet and lifestyle have become progressively more divergent from those of our ancient ancestors. Accumulating evidence suggests that this mismatch between our modern diet and lifestyle and our Paleolithic genome is playing a substantial role in the ongoing epidemics of obesity, hypertension, diabetes, and atherosclerotic cardiovascular disease. Until 500 generations ago, all humans consumed only wild and unprocessed food foraged and hunted from their environment. These circumstances provided a diet high in lean protein, polyunsaturated fats (especially omega-3 [omega-3] fatty acids), monounsaturated fats, fiber, vitamins, minerals, antioxidants, and other beneficial phytochemicals. Historical and anthropological studies show hunter-gatherers generally to be healthy, fit, and largely free of the degenerative cardiovascular diseases common in modern societies. This review outlines the essence of our hunter-gatherer genetic legacy and suggests practical steps to re-align our modern milieu with our ancient genome in an effort to improve cardiovascular health.

    ***
    Eur J Nutr. 2000 Apr;39(2):71-9.Click here to read Links
    Dietary lean red meat and human evolution.
    Mann N.

    Department of Food Science, RMIT University, Melbourne, VIC, Australia. neil.mann@rmit.edu.au

    Scientific evidence is accumulating that meat itself is not a risk factor for Western lifestyle diseases such as cardiovascular disease, but rather the risk stems from the excessive fat and particularly saturated fat associated with the meat of modern domesticated animals. In our own studies, we have shown evidence that diets high in lean red meat can actually lower plasma cholesterol, contribute significantly to tissue omega-3 fatty acid and provide a good source of iron, zinc and vitamin B12. A study of human and pre-human diet history shows that for a period of at least 2 million years the human ancestral line had been consuming increasing quantities of meat. During that time, evolutionary selection was in action, adapting our genetic make up and hence our physiological features to a diet high in lean meat. This meat was wild game meat, low in total and saturated fat and relatively rich in polyunsaturated fatty acids (PUFA). The evidence presented in this review looks at various lines of study which indicate the reliance on meat intake as a major energy source by pre-agricultural humans. The distinct fields briefly reviewed include: fossil isotope studies, human gut morphology, human encephalisation and energy requirements, optimal foraging theory, insulin resistance and studies on hunter-gatherer societies. In conclusion, lean meat is a healthy and beneficial component of any well-balanced diet as long as it is fat trimmed and consumed as part of a varied diet.

  5. “Saturated fat in the context of the modern diet (inactivity, high carb intake, obesity, inflammation) is distinctly unhealthy and the studies all support that. Saturated fat in the context of high activity, lots of vegetables, leanness) probably is no big deal and the studies support that too.”

    Yes! Also depends on genes I suspect. In all diabetes groups there appear to be one or two individuals who can genuinely make a high carb low fat diet work, which I now accept are genetic outliers.

    My specific diabetic gene set appears to convert saturated fats into HDL at the expense of LDL so long as my carb input is low enough to not spike my glucose and hence insulin levels. Not everyone can do this but it appears to be a common phenomenon, at least more widespread than the converse. Weirdly though (and familial) I have difficulty turning anything into body fat, the only diet that triggered weight gain was, you guessed it, the Heart Healthy High Carb Low Fat diet. Also eating more saturated fat greatly improves my energy and activty level, the above diet had me semipermanently exhausted.

    So I’m a genetic outlier at the other end of the continuum.

    I seriously wish I’d discovered this *before* spending 50 years eating muesli and brown rice.

  6. Regarding your response to Scrubby –

    It would help if you didn’t use papers authored by Loren Cordain, since he is a known saturated fat-phobe. While wild game is lower in fat than the typical corn-fed American beef, early man made it a point to seek out the fattest animals. When it’s your survival on the line, every calorie counts. Can you really see some paleolithic humans gathered around the fire, carefully cutting off the fat from their fresh kill? Studies have shown, using carbon isotopes from the bones of Neanderthal, that they were essentially carnivores. I doubt they had a fiber intake of 100-150 grams per day.

    Also – to quote from above “and generally contain the wrong types of fats (an excess of saturated and trans fats with insufficient amounts of healthy fats)” – seems to me like you are interested in demonizing saturated fat to a certain extent. Why else would it not be included in the “healthy fats”?

  7. Abe

    Read the summary another 4-6 times until the words makes sense. Your myopia that sat fat is ‘good’ is just as idiotic as the ‘myopia’ of others that it’s bad

    IT DEPENDS ON CONTEXT!

    Lyle

  8. Abe,
    Just wanted to point out that, although Neanderthals and Modern Humans had a common ancestor about 550,000 years ago, we are not decended from Neanderthals.

  9. Bruno,

    there are studies suggesting that high level of LDL is associated with a high carb intake. It is not what the LDL is made of, it is about how it is produced. If I recall correctly, with a high carb intake the liver starts churning out low density cholesterol.

    // Manne

  10. I really like your articles, easy to read and great information! The only thing im missing is links to all the studies you are referring too, but that’s just my curiosity!

    I read an article in the newspaper last night, a nutritional expert, who wrote that “fat wasn’t a part of our ancestors diets” she was referring to the stone age diet that people have been starting to use. She absolutely ment that they ate wild bird and low fat fish and stuff like that.

    Got me annoyed, slightly. 🙂

  11. ” I’d note that this effect primarily occurs when weight is lost; in studies of very low-carbohydrate diets where weight is gained, blood lipid levels often get much much worse.”

    I have not found this article. Could you please provide the reference link or at least which peer-reviewed article shows this?

  12. Krehl WA et. al. Some metabolic changes induced by low carbohydrate diets. Am J Clin Nutr (1967) 20: 139-148.

    Phinney SD et. al. The human metabolic response to chronic ketosis without caloric restriction: physical and biochemical adaptations. Metabolism (1983) 32: 757-768.

  13. Very well presented. While I would heartily agree with your perspective of carb intake varying from person to person based on goals, activity level, genetics, etc., there is one aspect of carb intake that I felt was not included in the debate that should have been considered. I apologize if it is presented/considered elsewhere in your articles and books. It seems that your main argument of basis for determining carb intake was relegated to hormonal effect and energy/caloric need. As there is no technical “need” for carbs as a source of energy, your argument was simply that carb intake be based subjectively on genetics, activity level, goals etc. However, it seems that the essential nutrients primarily found exclusively or at least largely in plant foods vs. animal based foods was ignored. For example, fiber intake was not mentioned. While I recognize that upper and lower fiber intake levels are debateable and not always well established, I do feel that there is a large body of research that supports the idea of higher fiber intakes correlate with better overall health. The question one may ask in this regard is how many carbs (and what kind) would one need to consume daily to reach the ideal daily fiber intakes? Would 20-50 grams of carbs a day provide enough dietary fiber to prevent the often constipated state that I often find in my high protein-high fat dieting clients? If we chose a low glycemic vegetable carb such as broccoli, 69 grams of carbs would provide close to the recommended daily intake of fiber of @ 38 grams (Institute of medicine). Again, I realize that these intakes are debateable. Some may argue that 15 grams of fiber daily may be sufficient. Vitamin and mineral content of plant foods should also be considered as certain levels are found exclusively in plant foods (such as Vit. C etc). I point these out not to argue one way or another, but merely to say they should be part of the consideration of determining ideal carb intakes.

  14. I noticed you said:

    “In our ancestral diet, fiber intakes were monstrous, averaging 100-150 grams per day. As well, despite the high fat intake, the source of that fat was far, far different than our modern intake. Much higher intakes of polyunsaturated and mono-unsaturated fats and far lower intakes of saturated fat were fairly typical.”

    I know you have the ability to thoroughly read studies and find the problems when it comes to body recomposition (BR). I really thank you for going through the literature since I don’t have the time to look through BR literature and find the holes, Im finding holes of my own in medical research.

    I really think you should read into more up to date literature from many journals ranging from medical journals to anthropological journals. You would then see that your above statement is not in line with what the science is saying as far as fiber and fat choices are concerned.

    You should know that some of the data sets used incorrect laboratory methods and these data sets are being cited in more recent papers. We know there are no known cultures that have consumed more than 100 grams of fiber, I believe the highest estimates are around 86 grams from some agrarian cultures in Africa. If you also look at the Womenʼs Health Initiative study you will see that fiber had no effect on weight loss, colon cancer and heart disease.

    The Hadza spit out excess fiber – http://www.mendeley.com/research/composition-of-tubers-used-by-hadza-foragers-of-tanzania/

    http://books.google.com/books?hl=en&lr=&id=6GDELypdTUcC&pgis=1

    Now if we look at saturated fat there are MANY studies and anthropological evidence showing this was a preferred source of fuel and is very stable in the human body (compared to polyunsaturated oils which are highly prone to oxidize). There is no one in the scientific community (doing good science) saying that polyunsaturated fatty acids in the form of n-6 is healthful (as a fuel source) and has been abundant in the human diet. Monounsaturated fat is also hard to come by in the prehistoric times (a very good fuel source nonetheless). That would have to be a lot of avocados, certain nuts and seeds and olives; which were very hard to come by.

    http://www.ajcn.org/content/early/2010/01/13/ajcn.2009.27725.abstract

    http://www.njmonline.nl/getpdf.php?t=a&id=10000756

    thanks for your continued research to help us look our best!
    Josh

  15. I agree with a lot of what’s written here. Humans evolved from meat eaters, 10,000 years ago most of our energy came from animal sources. The agricultural revolution sparked a change to plant based energy.

    I remember reminding someone in my jujitsu club of this when we were having a curry. He started going on about how it’s not real Indian food which is mostly vegetarian and humans have only recently started eating more meat. I told him that it depends on what you mean by recently and in evolutionary terms getting most of our energy from plants is very recent.

    One point frequently raised by vegetarians I do agree with is sustainability. Plant based food sources are a very cheap source of fuel. Doubling the amount of energy from animal sources would mean having to grow ten times the crops to feed the animals we eat. It’s just not sustainable, nor is it economically viable to go back to the stone age and get most of our energy from animal sources.

    Increasing the amount of fruits and vegetables is also difficult because they have a lower energy density than grains, sugar beet/cane, potatoes etc. A field containing broccoli with the same amount of calories as the field of corn would occupy a far greater surface area.

    The truth is, refined carbohydrates are a very cheap energy source and the alternatives are costly, both to us and the earth.

    What can we eat then?

    We could eat more soya but there are potential health problems there too.

    How do we avoid the health problems many of us are experiencing now whilst eating less meat?

    Of course nature will eventually sort it our for us, in the long term we’ll evolve to be healthy on our modern diet of cheap refined carbs but this will be a very slow and painful process.

  16. @melanie thank you for pointing that out!

    The fact that someone was using a Neanderthal as an example of prehistoric man was egregious.

  17. I amazed at how much shit that people give Lyle considering he’s just trying to help people like me. He’s not looking for compensation. Hell he barely talks about his own books except as a reference. I have a BS in Chemistry but I wasn’t aware of the all of the body’s chemical processes. I’m not sure it will ever click with me but I at least appreciate the effort.

    Thanks Lyle. Sheesh!

  18. Of course ancient humans weren’t cutting fat off meat. They didn’t have to to get lower fat intake. The point is that wild meats are lower in fat than modern meats. If you are eating modern meats, cutting the fat off would approximate the wild meat. While eating wild meat would be preferable, it’s hardly feasible for most people, not to mention having a tremendous impact on wild ecosystems if everyone did it.

    And while a small percentage of the European genome is indeed descended from Neanderthals, the vast majority is not and modern Europeans can hardly be equated with Neanderthals.

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