This post is an attempt to address the tons of fake advertising and little known science out there – some of it being passed down for several generations. Take care – if you listen to what I write about in these pages, you will most likely be laughed at by your family and friends.

Let me begin by first pointing out the biggest informational change rolling out into the world: For the last couple of decades, our dietary guidelines have been guided by this food pyramid. Grains are the bottom (the largest component) – this is why you eat “healthy” cornflakes, dalia, fat-free slices of bread, healthy dosas with olive oil.

This pyramid was published by the USDA in 1992 and has been fundamentally flawed in its measurement and it’s science. Thankfully, this was replaced by the “ChooseMyPlate.gov” depiction by the Obama Govt.

You see that they have eliminated the low consumption of fats. Why ? Should you now eliminate ALL fats ? Please dont do that, because that would be stupid. The reason that fats are not mentioned is because it is not possible to represent that in a minimal diagram like this.

Summary

Yes – the summary first. Fats are not bad.

Never replace any kind of fats (not even saturated fats) with carbs or poly-unsaturated fats. That will lead to an increased risk of heart disease. If anything replace saturated fats with mono-unsaturated fat or protein.

This means you cannot replace your 2 slices of bread and butter with 4 slices of bread with no butter. Or 4 eggs with yolks with 4 egg whites and a bowl of cornflakes

Jakobsen MU, O’Reilly EJ, Heitmann BL, Pereira MA, Balter K, Fraser GE, Goldbourt U, Hallmans G, Knekt P, Liu S, et al. Major types of dietary fat and risk of coronary heart disease: a pooled analysis of 11 cohort studies. The American journal of clinical nutrition 2009;89(5):1425-32. doi: 10.3945/ajcn.2008.27124.

Hooper L, Summerbell CD, Thompson R, Sills D, Roberts FG, Moore H, Smith GD (July 2011). “Reduced or modified dietary fat for preventing cardiovascular disease”. The Cochrane Library (7): CD002137. doi:10.1002/14651858.CD002137.pub2. PMID 21735388

An alternative way of looking at the same thing is (taken from Mprize)

that carb is really rather bad for overweight, insulin-sensitive people, such that replacing it even with Saturated Fats (SFA) is relatively harmless — whereas for lean, insulin-sensitive people, SFA (and dietary cholesterol, its fellow-traveller in omnivorous diets) is likely more relatively harmful, because carb is less able to derange the metabolism.

Until we get a couple of thousand healthy twenty-year-olds locked up in metabolic wards for sixty years or so for a really vigorous diet trial, I think saturated fat AND carbs (especially starchy carbs) stand out as things to reduce in the diet, in exchange for vegetables, fruit, lean protein, and PUFA (and probably MUFA) as things to maintain or increase. And most people should lose weight!

Anti-Summary

The biggest criticism for the above conclusion comes from what is popularly known as the Trichopoulou study, published in Nature magazine. Out of a total of 113 230 persons years of follow-up, the study found that High-Protein, Low-Carb Diet Leads To Higher Mortality Rates. There was a huge discussion on this on the LowCarber forums, where it was finally understood that the data used in the Trichopoulou study were extrapolated computer models that predicted only a slight increase in mortality rates.

Primarily, this study is also cited by various quasi-religious groups as justification for veganism.

Another study, By how much and how quickly does reduction in serum cholesterol concentration lower risk of ischaemic heart disease? – shows purported data from cohort studies of half a million men which makes a case for reduction of cholesterol in the diet. However, the comments on the same paper (at the same page linked previously) criticize pre-existing conditions as the cause for these changes and not dietary alone.

A short recap – PUFA, MUFA, HDL, LDL and heart disease

A lot of people know that some fatty acids are good and others are bad. Here’s the underlying science.

• LDL – Low Density Lipoprotein (bad!)
• HDL – High Density Lipoprotein (good!)
• PUFA – Polyunsaturated fatty acids (good – but gets bad, since it may get oxidized )
• MUFA – Monounsaturated fatty acids (good – This is where olive oil shines.)

PUFA vs MUFA vs Saturated Fats

(Taken from wikipedia:)

Allegedly, polyunsaturated fats protect against cardiovascular disease by providing more membrane fluidity than monounsaturated fats, but they are more vulnerable to lipid peroxidation (rancidity). On the other hand, some monounsaturated fatty acids (in the same way as saturated fats) may promote insulin resistance, whereas polyunsaturated fatty acids may be protective against insulin resistance.[1][2]

Furthermore, the large scale KANWU study found that increasing monounsaturated fat and decreasing saturated fat intake could improve insulin sensitivity, but only when the overall fat intake of the diet was low.[3] Studies have shown that substituting dietary monounsaturated fat for saturated fat is associated with increased daily physical activity and resting energy expenditure. More physical activity was associated with a higher-oleic acid diet than one of a palmitic acid diet. From the study, it is shown that more monounsaturated fats lead to less anger and irritability.[4]

In children, consumption of monounsaturated oils is associated with healthier serum lipid profiles.[7]

This is a very interesting paper that compares the pathways of saturated fat, PUFA and MUFA towards LDL and oxidation profiles. Here’s the conclusion:

• Consumption of an Saturated Fat (SFA) -rich diet resulted in higher LDL cholesterol than did consumption of MUFA-, PUFA(n-6), or PUFA(n-3)) rich diets. Aha… but we havent talked about HDL yet, which will balance out the LDL. This is what every doctor will tell you and stop there !
• HDL cholesterol was lower during both PUFA-rich diets than during the SFA and MUFA rich diets. There you go !!! Higher HDL helps the heart.
• LDL resistance to copper-induced oxidation, expressed as lag time, was highest during the MUFA-rich diet and lowest during the PUFA and SFA rich diets. Oxidation is really, really, really bad – that is one of the core causes of heart disease. So, higher resistance, the better. Covered in the next section.
• LDL induction of monocyte adhesion to endothelial cells was lower during the MUFA-rich diet than the other periods. _Again – monocyte adhesion is really bad. Lower, the better. _Covered in the next section.__
• In conclusion, an MUFA-rich diet benefits plasma lipid levels compared with an SFA-rich diet.

So, what we see is that PUFA and saturated fats are almost on par with respect to oxidation and other issues, however saturated fats are better in HDLs !! Really – think about it next time when you are using cottonseed oil instead of ghee (and we havent even talked about Omega-6 to Omega-3 ratios yet!)

Undoubtedly, MUFA is the best.

Creation of plaque in hearts = heart disease

The basic theory is around Chronic endothelial injury hypothesis – LDLs accumulate in the blood stream. This is followed by the attachment of leukocytes, monocytes and T-lymphocytes to these fatty acids. Once LDL accumulates, it tends to become oxidized (here is where HDLs help, since they help inhibit oxidation). In the presence of oxidized LDL, monocytes are converted to macrophages, which eventually forms fibrous plaque. In addition, oxidized LDL inhibits the endothelial Nitros Oxide pathway which leads to hypertension.

There are two ways to combat this –

1. lowering the blood levels of LDL
2. by discouraging LDL oxidation.

(huh… where did cholesterol go?)

The first approach is where there is a crap load of dis-information. For example, everyone thinks that reducing dietary cholesterol will help – but remember that dietary cholesterol increases both LDL and HDL and thereby maintains that balance (in fact “stearic acid”, a saturated fat, actually has much more HDL than LDL). There is therefore a lot of debate on which of the two pathways is better for reducing heart disease. It has not helped that the “margarine recommendation” (discussed below) has caused a lot of backlash against reducing total cholesterol intake.

Replacement of saturated fat with PUFA

Early studies around the whole saturated fat vs unsaturated fat caused the American Heart Association (AHA) to recommend switching to plant based PUFA from saturated fats. Now, this is the origin of hydrogenated vegetable oils like margarine which was sanctioned by the AHA in 1961. However, in 2006 the AHA reversed its recommendations – while it does not specifically ask to increased saturated fatty acids in diet, it no longer recommends switching to PUFA – especially because of its susceptibility to oxidation as well as the ratio of Omega-6 to Omega-3 in common oils like soya, cottonseed and corn oil.

Note the corn and soya oil – this is a huge, huge lobby in the US and is precisely why these studies never get popularised.

Omega 3 and Omega 6

Omega-3 is good, but Omega-6 is bad – Where we should actually have a ratio of omega6:omega3 of roughly 2-3:1, most people actually have ratios somewhere in the order of 30:1, due to mainly the consumption of the bad vegetable oils and the consumption of grain fed meats as well as grain fed cow butter and ghee. Eating a diet with little vegetable oils and opting for grass fed meat, you are able to bring your Omega6 consumption down drastically.

It has significant benefit in preventing colorectal cancer, prostate cancer, etc.

BTW, one of the best source of omega-3 (importantly – with low omega-6) is fish oil. Vegan sources are flax seed oil, mustard oil, etc. If you are eating butter and ghee, try to go grass feed cow butter and ghee to maintain your ratio.

BTW, check out the charts here – rice bran oil has lower ratio of omega-6 to omega-3. The lowest is mustard oil, but has a strong taste to use in food.

What is wrong with us today – a short history

There was a very interesting story that hit the mainstream very recently in Men’s Health magazine. Please go read that, it gives a very good idea of how the demonization of fats came about.

The first scientific indictment of saturated fat came in 1953. That’s the year a physiologist named Ancel Keys, Ph.D., published a highly influential paper titled “Atherosclerosis, a Problem in Newer Public Health.” Keys wrote that while the total death rate in the United States was declining, the number of deaths due to heart disease was steadily climbing. And to explain why, he presented a comparison of fat intake and heart disease mortality in six countries: the United States, Canada, Australia, England, Italy, and Japan.

The Americans ate the most fat and had the greatest number of deaths from heart disease; the Japanese ate the least fat and had the fewest deaths from heart disease. The other countries fell neatly in between. The higher the fat intake, according to national diet surveys, the higher the rate of heart disease. And vice versa. Keys called this correlation a “remarkable relationship” and began to publicly hypothesize that consumption of fat- causes heart disease. This became known as the diet-heart hypothesis.

In a 1957 paper, Yerushalmy pointed out that while data from the six countries Keys examined seemed to support the diet-heart hypothesis, statistics were actually available for 22 countries. And when all 22 were analyzed, the apparent link between fat consumption and heart disease disappeared. For example, the death rate from heart disease in Finland was 24 times that of Mexico, even though fat-consumption rates in the two nations were similar.

Despite the apparent flaws in Keys’s argument, the diet-heart hypothesis was compelling, and it was soon heavily promoted by the American Heart Association (AHA) and the media.

First watch this video – http://www.abc.net.au/catalyst/stories/3876219.htm . (This video caused a lot of doctors to revolt and protest that the next episode not be shown.)

There was another recent article in the highly respected British Medical Journal called Observations: Saturated fat is not the major issue – which again points out similar facts.

We have replaced all our fats with sugar and carbohydrates. We have become so used to “fat-free rice” that we replace perfectly good fats (like those found in egg yolks) with high carb replacements like poha or idli. Just checkout the amount of supposedly healthy recipes out there – everyone of them disavow fats for carbs, starches or sugars.

Doctors are increasingly prescribing statins for controlling cholesterol and is a huge huge business. There are official US govt statistics about huge increase of statin use – which in itself has various issues associated with it.

How do I diagnose heart disease ?

If there is a low correlation between saturated fats and blood cholesterol levels, how does one detect early onset of heart disease ? Every doctor that you go to recommends a “cholesterol test”. Unsurprisingly, it has become a big business where you can find discount coupons for heart rate and cholesterol test on Snapdeal.

There was a recent article by Harj Taggar – resident desi and partner at Y-Combinator – (and I’m quoting liberally from him) about how he got concerned about heart disease and went about trying to understand how to diagnose it. Now remember most doctors will throw the standard cholesterol test at you – which is really, really poor at accurately diagnosing heart disease risk.

There are four blood tests that are relevant (pricing data taken from http://www.delvin.co.in/tests.php):

• Apolipoprotein_B (ApoB) – approximate cost is Rs. 800 – This is a protein found on the surface of LDL (“bad cholesterol”) particles. A regular cholesterol test tells you how much cholesterol is contained within the LDL particles but doesn’t tell you either the number or size of these particles themselves. This test does that. Exercising reduces Apo(B) (though interestingly not LDL (“bad”) cholesterol)
• High Sensitivity C-Reactive Protein (hs-CRP) – approximately Rs. 850 – This is a protein found in the blood and its presence is a sign of inflammation in the body, which is a risk factor for heart disease. While testing for hs-CRP alone isn’t more predictive of heart disease than a regular cholesterol test, it does provide valuable additional information. eating omega-3 fatty acids reduces inflammation.
• Lipoprotein(a) (Lp(a)) – approximately Rs. 900 – This is a different form of LDL (Low Density Lipoprotein – also known as “bad” cholesterol) which attaches to a protein called Apo A. It’s apparently unclear what Lp(a) actually does but if your level is greater than 30mg/dL it’s deemed an increased risk factor for heat attack. It seems trickier to manage. It appears to be mostly hereditary.
• LDL/HDL ratio (this is my personal addition) – I would say this is also fairly important. Eating any kind of fat (especially saturated fat), increases both and one balances the other. he ratio of LDL to HDL is considered to be a marker of carotid plaque, or how much plaque you have built up in your arteries. The ideal levels are below 4.4; 4.4-7.1 is average risk for developing heart disease; 7.1 to 11 is a moderate risk of heart disease; and greater than 11 means you have a high risk of developing heart disease.
• Triglyceride/HDL ratio (again my personal addition) – there is strong correlation between this ratio and heart disease. Remember triglyceride is a marker of your carbohydrate levels. You ideally want this at the 2.1 level

There appeared to be evidence that all three taken together could provide a more accurate overview of heart disease risk than cholesterol alone. Here is more info about what your cholesterol tests mean.

Other factors to heart disease – stress and total calories

Please do not under-estimate the effect of stress and hyper-tension. Another important factor is reducing your overall calorie intake to reduce weight – calculate your resting metabolism rate and figure out how much you need to eat. All of these would arguably contribute more to the incidence of heart disease than dietary saturated fats.

The truth about Olive Oil

100 grams of Olive Oil – arguably one of the healthiest oils out in the world today, has 14 grams of saturated fat. Are you going to stop eating it now ?

There was a very interesting study conducted at UCSD:

LDL isolated from Greek subjects on a typical diet or from American subjects on an oleate-supplemented diet induces less monocyte chemotaxis and adhesion when exposed to oxidative stress.

The researchers analyzed LDL particles from 18 Greek, 18 American, and 11 Greek-Americans subjects (incidentally – everyone of them living in the United States ). They found

• no differences in the baseline lipid profiles among the Greeks, Americans, or Greek Native American
• 20% higher oleic acid content in the Greek compared with the American or Greek-American subjects – unsurprising considering the amount of olive oil they ingested.
• in vitro LDL oxidation (this is important as this may impact atherosclerosis and other heart disease) was lower in the Greek subjects. Incidentally, I’m not surprised at this result, because olive oil has shown to inhibit in vitro LDL oxidation.
• -42% reduced propensity for the attachment of of monocytes to mildly oxidized LDL was decreased (this is important because it’s part of the plaque build-up process)
• as pointed out int he previous section – this is inversely related to the oleic acid content of the LDL and is promoted by total LDL content.

Coconut Oil – the best oil out there ?

In case you are still worried, remember you can buy extra-virgin coconut oil. It tastes amazing and parathas taste lovely when cooked in it. Not to mention much cheaper than olive oil and better suited to the Indian palate.

Secondly, and more importantly, there are tons of studies now comparing extra virgin olive oil (EVOO) vs extra virgin coconut oil (EVCO) for health benefits. For example this and this.

However, it is still an under-rated oil in the rest of the world due to, well, its unsexiness. Hopefully that will change.