Calorie Budget Calculation

[Chris24Main]

Evidence that dietary saturated fat has a connection to LDL - study from 1998 - Link. This was a study that built on research carried out over the previous two decades. This study compared three diet plans - the average American diet (AAD), a diet titled 'Step 1' and a diet titled 'low-SFA'. The three diets vary by total saturated fat content.

I found that specific study by reading the references from a much more recent study which looked at the effects of a low saturated fat diet in African Americans specifically - Link. This one is interesting because it seems to show that going too low on saturated fat may elevate other risk factors, possibly for genetic reasons, or possibly not. Not eating enough saturated fat may actually be bad for a person. That represents the state of the art in saturated fat research. To find the evidence for the LDL thing you have to go back to the 80s and 90s, because it's very old news. Researchers try to answer questions left unanswered by previous research. Nobody spends years of their time trying to reinvent a 25 year old wheel or testing if that wheel still rolls. By reading some of the references on that paper, and then reading some of the references on some of those papers, and so on, I went back in time through the research to see how each piece of the puzzle was proven over time. That's how it's done. Have a go if you're interested. It does take a while, these things are hard to read, a lot of Googling unfamiliar terms involved, but it is a very informative process known as 'research'.

I stopped at this paper from 1997 which proved the mechanism by which saturated fats actually affect LDL particle concentration in the blood - Link. I felt I had kicked enough wheels by that point to be sure they were solid. Interestingly in reference to the cheese mystery I mentioned earlier, this study also used three diet plans - AAD, Step 1 and a Low-Sat. I believe the design of these studies is a flaw which might possibly have let cheese and other foods slip through the cracks, so to speak. Hopefully future research will examine individual foods rather than saturated fat as a broad grouping as if they were all the same (which they may not be).

To your second point, research on the connection between LDL (specifically) and causative effect in disease pretty much stopped some time ago because ApoB was determined some years ago to be the better marker to look for rather than LDL. Here's study from 2022 from China - Link - which looked at ApoB and all-cause mortality. That study did something interesting by also looking at markers for malnutrition. I'm not going to tell you what it says or interpret it for you because I don't think you'd take my word for it. If you are genuinely interested in seeing some evidence, as you say you need to, all you need to do it click on the links and read. I posted three of these three of these four links on this forum previously but, well.. things happen it would seem.

I'm no scientist. When I first joined this forum I believed that eggs are bad for health. I was of course wrong. They're only bad for a small subset of people who are genetically susceptible to high levels of dietary cholesterol, so called 'hyper absorbers'. I learned that, and everything else I needed to learn about cholesterol, so that I could determine which pieces of information posted on this forum are good and useful (eggs are in fact a fantastic food for most people) and which aren't factual. The work goes on and will never end, as there will always been some new science to read.

It isn't evidence though - there is no such evidence because there is no biological link between dietary fat of any kind and LDL - LDL is the result of VLDL once enough triglycerides have been transported such that the density drops - that's it. They are predominantly made in the liver. All the fat, whether saturated or not, is packaged up having been absorbed in the lower intestine, into particles called Chylomicrons. Saturated fat from the diet literally has nothing to do with LDL. You have to remember that the original version of this was "Cholesterol from food raises Cholesterol in the blood" - but it was so obviously wrong - even Ancel Keys himself had to change that to "Saturated Fat raises Cholesterol".. it's been downhill ever since.

Apo(b) is just the latest attempt to twist the data into something that makes sense of bad science - it will always be bad science. And when I'm talking about science I mean testing evidence.

All the studies, from the seven nation study in the forties onward, are simply suggestions of association, not evidence.

 

[Chris24Main]

Anyone perusing the science here needs to distinguish which experiments were conducted solely on men, and it's interesting how more recent studies that included women came to somewhat different conclusions. There is some way to go yet before hypothesis is supported by fact - and medical fact only lasts until the next study. So - a discussion well worth having, and thank you all for pursuing it.

Indeed - all the formative studies that led to the changing of the dietary guidelines that we still live with the consequences of, were studies of men who had already had a heart attack.

Not a single woman, and not a single metabolically healthy person.

 

[HairySmurf]

Anyone perusing the science here needs to distinguish which experiments were conducted solely on men, and it's interesting how more recent studies that included women came to somewhat different conclusions. There is some way to go yet before hypothesis is supported by fact - and medical fact only lasts until the next study. So - a discussion well worth having, and thank you all for pursuing it.

I'm not sure I follow. From the four studies linked above:

1: "We conducted a multicenter, randomized, crossover-design trial of the effects of reducing dietary SFA on plasma lipids and lipoproteins in 103 healthy adults 22 to 67 years old. There were 46 men and 57 women, of whom 26 were black, 18 were postmenopausal women, and 16 were men ≥40 years old."

2: "The mean age of participants was 35 years (range: 18–60 years). The majority of the participants were women (∼70%)."

3: "This study was conducted with 25 subjects ages 22-65 years (mean age, 37). Of these, 15 were male (2 African-American) and 10 were female [7 premenopausal (1 African-American) and 3 postmenopausal]."

4: The fourth study included 9,107 women (I think - I deduced that from table 1, I might be wrong).

There is a difference between women and men of course - estrogen - when it goes down, cholesterol goes up - Link. Pre-menopausal women are less susceptible to hearth health issues than men, and the situation changes some time after menopause when many more women start dying of heart attacks as they get older - Link. I'm sure there are studies that focus only on men, as I'm sure there are studies that focus only on women, because you can't compare directly between genders and in some contexts have to be studied separately - it's 'apples and oranges', because estrogen. Once that changes women rapidly start catching up with up with men as regards heart disease risk - Link

What am I missing?

 

[HairySmurf]

It isn't evidence though - there is no such evidence because there is no biological link between dietary fat of any kind and LDL - LDL is the result of VLDL once enough triglycerides have been transported such that the density drops - that's it.

One of the papers above proves the link which you claim doesn't exist. You are correct in what an LDL particle is and saturated fat has nothing to do with how that works. Saturated fat doesn't influence LDL particles, it influences the receptors in the liver that clear LDL particles from the blood. They changed people's diets and watched the LDL receptors change. Strictly speaking only a subset of saturated fat molecules to that - they went on to test that too, molecule by molecule.

I really don't get it. You ask for evidence, I dig up the link and hand it to you, and you claim the evidence, the experiment with scientists in lab coats and test subjects and peer review and the whole deal, doesn't exist? Or are you saying there's some flaw in the studies that renders them invalid? If so, please let me know so I can investigate further. It's an important topic.

 

[Chris24Main]

Estrogen is made from cholesterol .. of course that will happen. Cholesterol is so critical to so many parts of our bodies, it's insane that we think of it as something to get rid of.

Fully 20% of the total cholesterol in your body is in your brain, and all of it is made inside your brain, not a single molecule from diet, to coat synapses with. How can it be that we evolved to need a particle for so many things .. but somehow it furs up our arteries... in a mechanism that is also unexplainable...

The main problem - which I think we can agree on - is that you cannot acquire the kind of evidence I'm referring to, because you cannot do experiments on people. All these studies have that same problem - it's the same for me, I cannot prove what I'm saying by quoting studies either...

But - that doesn't change the facts - and the facts are that there is no biological connection between eating fat and the quantity of LDL particles in your bloodstream, it's all associations picked to prove a theory ...

 

[Chris24Main]

How did they watch the LDL receptors change?

I'm aware of studies that show liver cells in a petri dish become insulin resistant surrounded by saturated fat molecules - and that was on account of direct damage to the LDL receptors - but that wasn't people - in fact, (and this is Ben Bikman now) - the people who actually did the experiment have de-bunked this, because there is no way for such a thing to happen in a real person.

 

[Chris24Main]

The most obvious flaw in all the early studies is that they cherry picked the data in order to prove that saturated fat caused heart disease. There are even records from the congressional hearings where the reporter asked the senator running the committee something along the lines of "are you sure about this, the data is sketchy and this will fundamentally change the way we eat" and the senator answered "you sir, may have the luxury of time, we do not".

So, they had no idea at the time that smoking was bad, or that even the data they had was a better fit for sugar in the diet - I forget the personalities now, but in one of the first trials, the original data was re-built, and statistically analysed, and sugar was a marginally better fit for the conclusion that was drawn..

So, there's that.. but yes, all the original studies were very flawed, and went full in the face of the orthodoxy preceding for the previous hundred years, that sugars and starches were fattening.

 

[Chris24Main]

Sorry, I'm going to call myself to order here.. I don't want to derail this thread.. I'll step down off my soapbox..

 

[Outlier]

The woman's health differences aren't just about oestrogen. They are present before puberty and after menopause, plus a "fortunate few" never complete menopause and spend the rest of their lives with some of those symptoms - I'm one. Most interestingly is the difference in heart health and symptoms - women are often missed with heart attack, stroke and other heart issues because their symptoms are so different from the accepted norm, which was based on studies made on men. This was ignored in previous eras because of different social attitudes, and is a slight embarrassment nowadays wherever gender issues challenge biological differences. While that last is something outside this discussion, we do need to challenge any research that doesn't recognise what may differ between women and men in medical terms.

 

[KennyA]

I do think it should be noted that the American College of Cardiology, which had previously been gung-ho for the "saturated fat is bad, cholesterol will kill you etc" approach, has now (since 2019) completely switched opinion. I presume they have access to all the papers already quoted and have concluded that the 'evidence is not robust'.

The current opinion is:

• Several foods relatively rich in SFAs, such as whole-fat dairy, dark chocolate, and unprocessed meat, are not associated with increased CVD or diabetes risk.
• There is no robust evidence that current population-wide arbitrary upper limits on saturated fat consumption in the United States will prevent CVD or reduce mortality.

Here's the Abstract:

The recommendation to limit dietary saturated fatty acid (SFA) intake has persisted despite mounting evidence to the contrary. Most recent meta-analyses of randomized trials and observational studies found no beneficial effects of reducing SFA intake on cardiovascular disease (CVD) and total mortality, and instead found protective effects against stroke. Although SFAs increase low-density lipoprotein (LDL) cholesterol, in most individuals, this is not due to increasing levels of small, dense LDL particles, but rather larger LDL particles, which are much less strongly related to CVD risk. It is also apparent that the health effects of foods cannot be predicted by their content in any nutrient group without considering the overall macronutrient distribution. Whole-fat dairy, unprocessed meat, and dark chocolate are SFA-rich foods with a complex matrix that are not associated with increased risk of CVD. The totality of available evidence does not support further limiting the intake of such foods.

This is as close to a "we were wrong" statement as you're likely to get in medicine.

Link to the full review here:

https://www.sciencedirect.com/science/article/pii/S0735109720356874?via%3Dihub=&utm_source=arrow.proteinpower.com&utm_medium=referral&utm_campaign=the-arrow-188

 

[Lupf]

Thanks @KennyA, I've read this paper. It is very informative

Link to the full review here:

https://www.sciencedirect.com/science/article/pii/S0735109720356874?via%3Dihub=&utm_source=arrow.proteinpower.com&utm_medium=referral&utm_campaign=the-arrow-188

I like the illustration, see attached, which shows the change from saturated fat is bad to dairy,
to dairy, red meat and dark chocolate do not increase the risk of developing diabetes and cardiovascular disease

 

[HairySmurf]

This is a very good paper, many thanks Kenny. The gist is that arbitrary population-wide recommendations to lower saturated fat intake as a broad category of fats is unfounded. Can't argue with that. I found this text in that paper notable:

"Although there was also a positive relation of saturated fat intake with all-cause mortality, this became significant only with intakes well above average consumption. Notably, the diet with the lowest hazard ratio for all-cause mortality comprised high fiber (10 to 30 g/day), protein (14% to 30%), and monounsaturated fat (10% to 25%) intakes and moderate polyunsaturated fat (5% to <7%) and starch (20% to <30%) intakes. For dietary carbohydrate, higher consumption (mainly from starchy carbohydrates and sugar) was associated with a higher risk of CVD and mortality. In the context of contemporary diets, therefore, these observations would suggest there is little need to further limit the intakes of total or saturated fat for most populations. By contrast, restricting carbohydrate intake, particularly refined carbohydrates, may be more relevant today for decreasing the risk of mortality in some individuals (e.g., those with insulin resistance and type 2 diabetes)."

The gist of the paper is not that eating loads of saturated fat is fine, it's that some specific saturated fats are worse than others, some foods containing saturated fats are much better than others for overall health, and that pushing total saturated fat in the diet to very low levels is not a good idea.

"In recent decades, however, diets have changed substantially in several regions of the world. For example, the very high intake of saturated fat in Finland has decreased considerably, with per capita butter consumption decreasing from ∼16 kg/year in 1955 to ∼3 kg/year in 2005, and the percent energy from saturated fat decreasing from ∼20% in 1982 to ∼12% in 2007. Therefore, the dietary guidelines that were developed based on information from several decades ago may no longer be applicable."

Incidentally, rates of deaths due to heart disease in middle aged men in North Karelia in Finland reduced by 82% between 1972 and 2012. It's impossible to know what part of this reduction was due to diet changes and what was due to reductions in smoking though.

The full text of that study is well worth reading. Every word.