Where Are We Today?

When I started this blog back in 2005, in my second post, Hunter-Gatherers, I looked at a review by Loren Cordain et al, about the maronutrient estimations in worldwide hunter-gather diets.

I noted,

Their findings included

• Most (73%) of the worldwide hunter-gatherer societies derived >50% (56–65% of energy) of their subsistence from animal foods, whereas only 14% of these societies derived >50% (56–65% of energy) of their subsistence from gathered plant foods.
  
  
• This high reliance on animal-based foods coupled with the relatively low carbohydrate content of wild plant foods produces universally characteristic macronutrient consumption ratios in which protein is elevated (19–35% of energy) at the expense of carbohydrates (22–40% of energy).
  

So, most of the hunter-gathers are eating 56-65% of their energy from animal foods, providing 19-35% of their calories as protein and just 22-40% of their calories from carbohydrate.

In a "real world" 2000-calorie a day diet, what does such a macronutrient mix look like?

19-35% of calories from protein = 380 to 700 calories or 95g to 175g of protein, with most coming from animal foods

22-40% of calories from carbohydrate = 440 to 800 calories or 110g to 200g of carbohydrate

The remaining calories, from fat = 500 to 1180 calories, or 25-59% or 55g to 131g of fat

And continued by stating that "[t]hese ratios are very much in line with controlled-carbohydrate nutrition ratios, which generally holds that carbohydrate is limited to 40% or less for daily calorie intake. The mix of fat and protein calories in a controlled-carb approach is highly individualized and the goal is to include quality protein in adequate amounts and only include quality fats and oils."

Six years later, I still hold the opinion that today, controlled-carb nutrition can model the diet of our ancestors; typically called Paleo and/or Primal eating. In fact, I'd say it would be difficult to consume a diet high in carbohydrate (greater than 40% of calories from carbohydrate) without specifically focusing on eating a high level of carbohydrate each day.

Has this become clearer in the years since I started this blog?

Not really.

In truth, time has created a variety of differing opinions that leave many confused; worse is that some seek to create divisions where none need be.

Recently Jimmy Moore posted AHS12: A Dichotomy Of Differing Interpretations Of What Paleo Is. In it, he writes, "However, when it comes to starchy carbohydrate sources of nutrition such as white potatoes, sweet potatoes or white rice (the toxin-free “safe starches” identified as such by Paul Jaminet), there’s a definite divide between those who avoid them because they raise blood sugar and insulin levels as well as lipid numbers to unhealthy levels (...) and those who believe these starches provide the adequate glucose your body needs to perform and function as it was intended to. That’s quite a division within the Paleo community that doesn’t have an easy answer to bridge the chasm."

Is this really a division within the Paleo community? Is this really a chasm that needs a bridge?

Honestly, I don't think so.

As I noted in my comments on his link to the blog on Facebook, "Paleo is a guideline to the types of foods one can eat, not the amount one *should* eat of any particular macronutrient; low-carb is one dietary approach which fits in with a paleo diet. Both focus on quality protein, good fats and nutrient dense carbohydrate. What level of carbohydrate you consume is your business, Paleo is basically just the framework for what foods to choose from. I don't think paleo has to be low-carb to be effective. It really is dependent on the individual."

One of the things I've learned over the last decade is that nothing is set in stone when it comes to macronutrients - the diets of healthy, normal weight individuals, around the globe vary greatly, what matters most is the micronutrient composition in the overall diet; it's habitually meeting or exceeding essential fatty acids (EFA), essential amino acids (EAA), essential vitamins, minerals and trace elements. The Japanese do that by consuming copious amounts of fish and pork, but their overall diet is lower in fat than those in France, who also do that with a wide variety of meat, full-fat dairy and a boatload of non-starchy vegetables and fruits. Both diets also have starchier foods too, yet these populations are not, nor have they ever been, suffering alarming rates of obesity.

Why?

If you look at diet quality, both Japan and France are eating serious quality foods, real foods, compared to the US and other nations with exploding obesity rates.

Quality matters; it is the heart-and-soul of Paleo, it is the heart-and-soul of Primal. The focus of ancestral eating (Paleo and Primal) is real food, shunning the processed and choosing quality. It defines no specific level of macronutrients by gram or percentage, but does point to nutrient density and meeting essential nutrient requirements. While one can follow a low-carb diet and eat Paleo-Primal style, that does not mean Paleo-Primal is low-carb per se; although, as noted i the paper by Cordain et al, Paleo-Primal diets are lower in carbohydrate than the Standard American Diet (SAD).

I do not think we have this deep divide, I think what we're seeing is a wide variety of approaches to reach the same goal - eating healthfully for the long-term. For some that includes soaked and fermented grains (Weston A. Price Foundation), for others eliminating grains is important, but dairy and legumes, along with other foods that are newer in our history may be included (Primal), and still there are those who hold that those foods, eaten by others in the spectrum of eating "real food", are simply unacceptable, just say no (Paleo). At the end of the day, the common theme amongst all - eat real food!

As one commenter noted on Jimmy's blog, "We do not currently understand everything about the variation in individual response to carbohydrates, such as sex differences, or dependence on history of metabolic dysfunction. We also do not completely understand how an individual’s dietary needs may change as a function of time depending on external
conditions. In addition, how much carbohydrate a person will do best on will depend on their goals (performance, longevity, reproductive health), but once again we do not understand the complete picture!"

I concur! Many things factor into weight loss and long-term health, eating real food is the one thing that continues to be the most important aspect of a healthy diet.

Chris Kresser nailed it last year, in his post Beyond Paleo: Moving from a Paleo Diet to a Paleo Template.

Review Time

Back in 2007, I did a series on the "rules" of Atkins. Here I present the links to that series and will follow-up in the coming weeks with lessons learned and a view of the long-term.

• Handing you the Keys to Success
• Establishing Good Eating Habits: Rule One
• Rule Two: Back to Basics
• Rule Three: Vegetables & Fruits are Heart of Controlled-Carb
• Rule Four: Starches, Sweets: No Longer Staples
• Rule Five: Break Free from Contradictions
• Rule Six: Empower Yourself
• Rule Seven: Use Your Smarts!
• Rule Eight: Keep it Real
• Rules to Drink it Up!
• Rules to Maintain a Balance

Babaganoush

Apologies for no picture!

Babaganoush - 8 servings

2 large eggplants (about a pound)
1 medium red tomato
1 thick slice red onion (about 1")
1 Tbs ground nutmeg
2 tsp crushed garlic
Juice from 1/2 medium lemon
2 Tbs Tahini
3 Tbs pine nuts (pignoli)
4 Tbs EVOO

Preheat oven to 400 and place eggplants on baking sheet. Bake at 400 for 35-40 minutes.

Remove from oven and allow to cool. Peel the skin and discard, cut up eggplant and place in large bowl.

In a small bowl, set aside 2 Tbs of olive oil, add the remaining olive oil to the eggplant.

Add all remaining ingredients (except the pine nuts) and blend with an immersion blender until smooth.

To serve (makes 8 servings), top on lettuce or a thick slice of tomato, top with olive oil and pine nuts.

Per Serving (8) including topped with EVOO and pine nuts: 16g fat, 12g carbohydrate, 3g protein
NOTE: Carbohydrate is net; total less fiber

Rule Seven: Use Your Smarts!

It's almost impossible to miss the recommendation to read labels on food packages these days. It's good advice no matter what dietary approach you decide to follow, and is front and center in the Rule of Induction (Atkins) too, found in rule number seven.

Rule 7:

• Don't assume any food is low in carbohydrate - instead, read labels. Check the carb count (it's on every package) or use a carbohydrate gram counter.

This rule establishs a lifelong habit that, as you continue along with a controlled-carb diet, will be invaluable to you. You're expected to make it a habit to read labels and take responsibility for your food choices at the start of a low-carb diet and as you continue along and lose weight.

Once firmly rooted as a part of your food selection process, reading labels makes you a smart and savvy shopper - with an ability to quickly identify packaged foods that are not your best bets nutritionally.

While the first couple weeks has an underlying encouragement to limit foods to those which are fresh, it is possible to include a wide variety of prepared and/or packaged foods, thus the potential to derail success if you're not careful with your choices. So, in the first couple of weeks this rule is invaluable anytime you're including packaged processed foods in your menus.

The reality is that most people will include some packaged foods, whether salad dressings or prepared foods, from the start; so making it a habit to read labels reinforces the requirement that one take responsibility for what they eat.

Over time, reading labels helps to develop a keen eye while enabling one to make good choices among the packaged foods they include in their day-to-day menus. As more and more variety is added to a low-carb diet, it is critically important to be in the habit of reading nutrition labels - not only for carbohydrate content, but to understand ingredients used since differing brands of same-type items varying greatly not only in carbohydrate content, but ingredients used in the preparation of the packaged or prepared food.

Rule Six: Empower Yourself

You may recall that in rule one of the Rules of Induction (Atkins), those starting the first phase of the diet are reminded to eat regularly and develop a pattern of eating each day that they're comfortable with, be it three meals a day or four or five. Also within that rule was the caution not to go more than six waking hours without eating something. I bring rule one up again today because it complements rule six, which says:

Rule 6:

• Adjust the quantity you eat to suit your appetite, especially as it decreases. When you're hungry, eat the amount that makes you feel satisfied, but not stuffed. When you're not hungry, eat a small controlled carbohydrate snack to accompany your nutritional supplements.

Where rule one speaks to our need to establish good eating patterns to take with us as we lose weight and then maintain our weight, this rule helps us understand that over time, as our weight declines, our food intake will decline and we still need to be aware that even with a diminished appetite, it's important to nourish our bodies for good health.

So many diets play on our fears - and one of the biggest is our fear that we lack enough willpower to actually stick with a diet long enough to lose the weight; forget about keeping it off!

One of the draws of a low-carb diet is the natural appetite suppression that comes within a few days of carbohydrate restriction. A large number of studies have noted that even when allowed ad libitum access to any and all of the foods allowed on a low-carb diet, those who stick with the allowed foods experience a "spontaneous" reduction on caloric intake while consuming an adequate level of protein and dietary fats to sate appetite and lose weight.

Sometimes the appetite suppression is so good that it's easy to miss a meal or go without eating too long. This rule reminds us that adjusting our food intake as we lose weight is expected, but we do not need to limit our intake to a point where we're potentially doing more harm than good, nor to we have to rely solely on willpower to lose weight or live with hunger pangs as we lose - we need nutrients from food, we need energy from food (even while losing weight) and we need to establish good eating habits.

That means eating for both to nourish the body and to sate appetite; adjust how much you eat to satisfy your appetite, allow yourself - give yourself permission - to eat and feel satisfied. Satisfaction with your meals keeps you motivated as you lose weight.

This rule does have a caution and that is to be aware not to overeat and stuff yourself, not to gorge or binge. For some who are new to low-carb this may be something that could become problematic - eating too little and then binging - so the caution is there to listen to your body, pay attention to your appetite and learn when you're hungry and when you're satisfied. Over time, if you're paying attention to this you'll find your body really does trigger hunger when you're hungry and if you're eating well, establishing an eating pattern happens!

The last part, to include a small carbohydrate controlled snack with your supplements, reminds us that including nutritional supplements is considered a benefit on the diet and eating something small with them can help you with rule one to establish good eating habits!

Over time as you lose weight, your appetite is going to naturally diminish and your energy requirements will adjust too. This is something to be aware of for the long-term - what you eat when you start - whether it's 3000-calories or 2000-calories - is going to slowly decline in time as your body weight is reduced. Someone who weighs 300-pounds needs more calories each day to maintain their weight than someone who weighs 150-pounds. So, in the long term, this rule is establishing this in your mind to remember later, as you reach a lower weight - you won't eat the same as you do at the start of the diet!

Overall this rule fosters a sense of empowerment - the understanding that you can, perhaps for the first time in your life, listen to your body and learn how to eat well over the period of losing weight and then as you maintain your weight!

Rule Five: Break Free from Contradictions

Thus far we've looked at four of the Rules of Induction for the Atkins diet. I've used the Atkins diet rules because no matter which low-carb diet one chooses, these rules have little "gems" that can broadly apply to any controlled-carb diet based on its design, carbohydrate restriction and/or phases.

Today, we'll look at rule five. At first glance, it appears to be in a rather harsh tone toward the reader:

Rule 5:

• Eat nothing that isn't on the Acceptable Food List. And that means absolutely nothing. Your "just this one taste won't hurt" rationalization is the kiss of failure during this phase of Atkins.

Simply put, this rule is reinforcing the importance of being able and ready to begin something new and different while letting go of the "diet baggage" we all had/have that will not serve us well throughout weight loss on a low-carb diet, and certainly not when we maintain our weight later. The only way to say it is straight-out and without sugar-coating it - if you start the diet with bad habits and do not address them, they'll be your undoing on this diet (or any diet) you want to utilize as your means to lose weight.

This rule makes clear that everything on the 'acceptable foods list' is allowed, go and enjoy these foods; those not on the list are not allowed right now - not even one bite, not even if you can manage to include them within your carbohydrate allowance for this period. The time frame here is two weeks and you will not die without the foods that are excluded during this period.

You may crave them, want them, think you need them - but what you 'want' is not always what you 'need' and for now, there are plenty of nutrient-dense foods you are allowed to eat, so take this period to eat those and only those foods; more variety will come in time.

Many wonder why this rule is so harsh. In part it is helping to break habits of the past, in part wiping clean years of eating foods that were not the best choices for health and well-being, in part imploring you to ignore many current dietary contradictions, and in part to help you naturally supress cravings for carbohydrate-rich foods.

Did you catch that last item?

It is true for the vast majority of those starting a low-carb diet; if you can simply stick with the 'acceptable foods list' for your first two weeks, you'll find that cravings for carbohydrate-rich foods diminish quickly and by the end of two-weeks, they're supressed so you no longer think much about having bread or pasta or potatoes or sweets.

Now granted, these foods will always be around you; but you will now have a powerful way to make them less tempting in the future if you can avoid them completely for a couple of weeks.

In the process you'll be rewarded for your efforts and discipline too - you'll lose weight in the first two weeks, find you have more energy at the end of the two weeks, and also realize that the foods you used to reach for in times of stress or to celebrate can be replaced by foods that are better for you and your health.

What this two week period is teaching for the long-term is that you ultimately control what you choose to eat. It is a period that is allowing you time to step back from everything you think you know, retreat from all the contradictions we hear from the "experts," step back from all the habits you've developed over the years, and start again - at the basics.

This particular rule goes against everything we hear and read so often; on the one hand we're repeatedly told part of the underlying reasons for obesity is lack of willpower and discipline; on the other hand we hear often this insistence that if you want something eat it, if you're on a diet and craving whatever it's better to eat it than to not because it's not good to deprive yourself of something you want.

How in the world is one supposed to develop this necessary discipline if they're never challenged and expected to discipline themselves?

As I said, this rule sets a standard for you to hold yourself to, that for a short period of time - two weeks - you will avoid any food that is not on the accepted food list so you can prove to yourself some big things:

• What you think you want to eat isn't always what you need to eat
• Food is not the enemy, nor do you lack willpower; given adequate time and nourishment, your body will help you re-learn how to eat well
• You really don't have to punish yourself to lose weight with feelings of hunger, eat what's allowed and you'll be sated
• You really are empowered to make good decisions and eat delicious food while you lose weight
• You'll really get to experiment and play more with your eating later, as you move forward and continue to lose weight

These first two weeks extend to the longer term as you are empowered to listen to what your body is telling you; you'll initially get over the idea you need starchy or sweet foods all the time, and then understand as you continue, when and where these foods will fit into your long-term menus. Once again, you'll also begin to appreciate just how good real food tastes, and take the foods from these first two weeks into your long-term eating, so they serve as your foundation for the future.

Back to Our Regularly Scheduled Program

You may recall the alarming headlines reported here that suggested a high-fat meal was very risky to endothelial function; one went so far as to suggest just one bite of a burger might kill you!

Seems some researchers thought maybe it's a good idea to see what effect a high-protein (low-carb) and low-fat (high-carb) habitual diet might have on endothelial function over a longer period of time - say, maybe a year?

Wonder why you haven't seen any headlines on the latest study - Effects of weight loss on a low-carbohydrate diet on flow-mediated dilatation, adhesion molecules and adiponectin - published in the British Journal of Nutrition?

Might be because the researchers found nothing significantly different between the two diets, and noted "weight loss does not improve FMD [flow mediated dialation]."

Paper gets published, media sees it, notes noting to see here, no sexy headlines....not quite juicy enough to waste readers time with (even though it contradicts those one-meal experiements), so let's just move on.

But wait!

Just because the study objective was to see effect (benefit or risk) on FMD, adhesion molecules and adiponectin, was there anything else they measured that did have significance and is worthy of our time to look at?

How about we take a look?

Two groups of subjects were randomized into two different dietary protocols - the first included 13 people assigned a low-carbohydrate diet (40% protein, 27% carbohydrate and 33% fat; 26g fiber daily); the second included 12 people assigned the high-carb diet (20% protein, 60% carbohydrate, 20% fat; 40g fiber daily).

Both groups were weighed, measured, poked and prodded and followed up with a 6-weeks, 12-weeks and 52-weeks. Measurements and testing included weight, BMI, blood pressure, cholesterol, glucose, insulin, CRP, VCAM1, sICAM1, E-selectin, P-selectin, and total adiponectin. In addition, vascular measurements were taken for blood pressure analysis and endothelium-dependent FMD, along with an assortment of other tests.

The various measurements were duly recorded for baseline and re-measured during follow-ups, and were included in the final paper. Some critically important measures were statistically significant, but not the focus of the study design; thus not highlighted in the abstract conclusions.

We hear a lot about how low-carb diets are bad for cholesterol.

In this study, like others, total cholesterol, LDL and triglycerides were lowered over the course of the year and HDL rose while following the low-carb diet.

Total Cholesterol:
Baseline = 5.3
52-weeks = 4.62
[low-fat group went from 5.7 to 4.94]

LDL:
Baseline = 3.5
52-weeks = 2.69
[low-fat group went from 3.8 to 3.07]

HDL:
Baseline = 1.3
52-weeks = 1.44
[low-fat group went from 1.3 to 1.34]

Triglycerides:
Baseline = 1.7
52-weeks = 1.07
[low-fat group went from 1.4 to 1.34]

Intriguing too was the improvements with glucose and insulin following the low-carb diet:

Glucose (fasting):
Baseline = 5.9
52-weeks = 5.19
[low-fat group went from 5.8 to 5.5]

Insulin (fasting):
Baseline = 16.9
52-weeks = 7.28
[low-fat group went from 12.1 to 5.22]

An interesting finding was that adiponectin, a hormone involved in a number of metabolic processes, including glucose regulation and fatty acid catabolism, "did not change significantly after 12 weeks of weight loss" (p=0.10), but increased (good) at the last measurement, 52-weeks, at the end of the study (p=0.05).

Blood pressure (not high at baseline) improved, from 122/75 at baseline to 115/68 at the 52-week measure; for those on the low-fat diet, blood pressure increased from 122/75 at baseline to 130/74 at 52-weeks.

It's clear in the data that both dietary approaches offered improvements with weight loss in the above measures of risk factors. Something though wasn't "right" to help with, improve, endothelial-dependent FMD. We'll explore potentials in a moment.

Somethign troubling that seems glossed over - the higher blood pressure in those following the low-fat diet - where at baseline their blood pressure averaged 122/75, at 6-weeks it improved to 115/72 and again improved at 12-weeks was similar at 118/70. What happened between the 12-week measure and the blood pressure reading at week 52, when blood pressure was now averaging 130/74?

This is something I would consider worthy of noting, even maybe point out and suggesting additional questions and investigation as to why!

In the discussion section, the researchers stated that "The main finding of the present study was that weight loss on a low-carbohydrate diet which brought about reductions in glucose, insulin and LDL-C did not improve FMD either after short-term weight loss or long-term weight maintenance. Irrespective of diet composition weight loss had beneficial effects in the short term on adhesion molecules and blood pressure and in the longer term on adiponectin and P-selectin. There appears to be a delay in improvement in both adiponectina nd P-selection as these molecules did not improve until weight loss had been maintained for a year."

They went on to add, "Lack of change in FMD in the present study confirms our previous finding that weight loss does not improve FMD...One of our goals with the dietary intervetion was a reduction in LDL-C which we achieves, 18% at 6-weeks and nearly 30% at the end of the study with no effect on FMD."

The researchers also noted that "The present study was also designed to achive a reduction in glucose in a 6-week weight loss intervention on a more moderate diet of 6000kJ and we achieved this but with no effect on FMD."

And, "A complex physiological response such as FMD may be related to LDL and glucose cross-sectionally and in post hoc analyses but these may not be casually related but correlate in some circumstances with the real unmeasured mediator of change. For instance, oxidative stress may be a major factor in reducing NO bioactivity but reducing LDL levels may have no effect on this even though the endothielial cell is clearly heathier as judged by a reduced adhesion molecules."

In the end, they concluded that "weight loss on a low-carbohydrate, low-saturated fat diet, does not improve FMD despite improvement in cardiovascular risk factors. The improvement in adiponectin was delayed."

So what was their error of omission?

Well, for one they failed to note the problematic rise in blood pressure observed in the subjects following the low-fat diet. But, let's set that aside for a moment.

They also failed to note that the above failure to improve FMD was also observed in subjects following the low-fat diet; one that happened to be designed well enough to match the American Heart Association recommendations!

Yet even that low-fat diet (20% of calories from fat) didn't help improve FMD, despite their weight loss, improvement in glucose, insulin and cholesterol; but this was left unsaid.

I'm not surprised.

So, what we're left with is the stated null finding of those on the low-carb diet, with no real statement that neither dietary approach did much for FMD.

I hate to say it, but there was also a lack of curiosity as to why this was.

It's pretty much accepted dogma that a low-fat diet improves the cardiovascular system, thus would exert a postive - significant - effect on endothelial-dependent FMD. It didn't, yet the researchers didn't say "hey, wait, this low-fat diet didn't help either" and instead highlighted that the low-carb diet didn't improve FMD in their conclusions.

Some questions really do need to be asked.

First, how did the low-carb diet look compared with the habitual diet?

We know subjects were consuming, on average, 11.4mJ each day (2725-calories) as their habitual diet. The weight loss diet was 6000kJ each day (1430-calories). They followed the weight loss phase of the diet for six weeks and lost 5.8kg, or 12.75-pounds.

Let's do math!

Each day, we're to believe, the subjects were in a calorie deficit of 1295-calories. Six weeks is 42-days, so over the period, a calorie deficit of 54,390 calories - enough to theoretically lose 15.5-pounds. Hmmm....Okay, so it's pretty clear they did not really follow the diet as planned, since it's clear they consumed more calories than was reported. Happens all the time, no biggie.

Except, we have no idea what the excess calories were, so we have a confounding variable here. Did they eat pie? Did they eat broccoli? Did they eat fatty meat instead of lean meat? Did they skip the oatmeal and eat eggs? Who knows?

It's also noteworthy that the low-fat dieters ate a habitual diet of 10.8mJ daily (2581-calories) and were placed on the same weight loss calorie level. So they were in a calorie deficit of 1150-calories each day, or a six week deficit of 48,342-calories. This theoretically would result in a weight loss of 13.8-pounds; they lost 5.9kg (13-pounds). Did they cheat less? Did they stick to the diet more carefully? Who knows?

But, we can be sure we have a confounding variable here - something doesn't add up, and it looks like that something is calorie intake. It appears it was higher than the dietary protocol called for; and an increased calorie intake we have no idea what foods/macronutrients it came from.

So then, is there anything else? Let's see how macronutrient intake changed on the low-carb diet.

At baseline, their habitual diet - 2725-calories - was from 39.6% carbohydrate (270g), 19.6% protein (133.5g) and 36.5% fat (110.5g). We do not know the baseline intake for fatty acids, but do know the dietary protocol was strict - saturated fat 7%, PUFA 6% and MUFA 13% of calories.So, while following the weight loss diet, the macronutrient profile changed to provide 1430-calories each day, of which 33% were carbohydrate (118g), 40% protein (143g) and 27% fat (43g) with 7% from saturated fat (11.1g), 6% from polyunsaturated fat (9.5g) and 13% from monounsaturated fat (20.7g).

The first glaring disparity is the protein-to-fat intake, for every 1g of fat, they were expected to consume 3.3g of protein; this is a highly unusual pattern, heavy with protein and too lean - if you review other studies on "low-carb" diets, the fat intake is usually higher than the level in this protocol and protein typically lower; of note, this intake ratio is next to impossible without some funky planning. I'd like to know how much soy was a part of this diet? How much of the diet was comprised of non-fat dairy? How much fish was allowed, and what type was it? Were protein shakes or supplements part of the protocol? If so, which type of isolate dominated?

Without this specific data, it's difficult to say one way or another if the foods included may have contributed to the null finding or not.

So here, we have a potential confounding variable that is unexplored.

Anything else?

Well, from the data we do know, it seems we find an inadequate level of polyunsaturated fats - with just 9.5g each day; a level at which the subjects are unable to meet essential requirements for omega-6 or omega-3 fatty acids!

I am really starting to wonder why researchers designing diet protocols that are inadequate for known essential nutrients?

The Institute of Medicine (IOM) clearly states in the Daily Recommended Intake documentation, the MINIMUM required each day from omega-6 is 5% to 10% of calories and the MINIMUM requirement each day from omega-3 is 0.5% to 1% - when calories are adequate to maintain weight. In absolute terms - absolute gram minimums - the IOM states that adequate intake of omega-6 fatty acid is 14g-17g for men (depending on age) and 11g-12g for women (depending on age); and that adequate intake of omega-3 fatty acids is 1.6g for men and 1.1g for women.

Combined, the absolute minimum intake for essential fatty acids is between 15.6g-17.6g for men and 12.1g-13.1g for women.

In this study, even if every last gram of polyunsaturated fat was an omega-3 or omega-6, these subjects were deficient for essential fatty acids with only 9.5g of polyunsaturated fats as part of the diet.

So, again, confounding variable - huge confounding variable!

And the researchers question why the diet didn't have an effect on FMD?

Perhaps the researchers haven't read the data showing improvement in cardiovascular health when essential fatty acid intake is optimized to meet or exceed current recommendations?

Recent evidence of the role of omega-3 polyunsaturated fatty acids on blood pressure control and hypertension-related complications

Omega-3 Fatty Acids: Role in Cardiovascular Health and Disease

Fish Oil and Endothelial Function

I can't say it enough - I love good data, but studies like this, with macronutrient intakes, as percentage of calories, is highly confounded data. Designing a dietary approach to lose weight or maintain weight, macronutrient percentages are often inefficient and do not meet essential nutrient requirements.

I'd really like to see some researchers start designing studies to ensure adequate intake of essential nutrients within the calorie deficits - until we start to look at the nutrient-quality of weight loss diets, I'm afraid we're not going to make much progress to provide the public with sound, scientifically supported recommendations.