Consider me vexed. I’m displeased with the misinformation about dietary fat as some kind of miracle macronutrient. In the majority of cases, you should not be trying to put more fat into your diet. But that’s not what the media is telling you.
“The low carb / high fat guys heard that saturated fat may not be as bad for you as we thought and took that to mean it’s actually good for you, then started putting butter in their coffee.” This from Dr. Spencer Nadolsky, a family physician specializing in obesity that walks the talk of a healthy lifestyle.
There has been a glorification of saturated fat of late. Most notable was the buttery image on the cover of TIME Magazine a few years ago, written by the magazine’s foreign editor, with the title “Eat butter.” More recently, TIME had another piece entitled “The case against low-fat milk is stronger than ever.”
Except it’s not.
This is what happens when you have generalist reporters who don’t understand nutrition very well pretending they understand nutrition well, or even pretending they know what makes for a good study. And why would they if such knowledge gets in the way of a catchy headline and clicks and shares from those who want a confirmation bias for their belief that lots of butter-soaked bacon is a great idea.
Nutrition expert Alan Aragon referred to the studies referenced in TIME’s milk article as “epidemiological schlock.”
Aragon is even hesitant to call them “studies,” because they’re strictly observational and can’t make claims of causation. What claims are those? The first study referenced of 3,333 adults and published in Circulation discovered that “people who had higher levels of three different byproducts of full-fat dairy had, on average, a 46% lower risk of getting diabetes during the study period than those with lower levels.” And the study author, Dr. Dariush Mozaffarian, wants health organizations to start recommending consumption of higher fat dairy.
The second epidemiological study referenced is of over 18,000 women and found that those who consumed the most high-fat dairy products had an 8% lower risk of being overweight or obese.
So that means higher fat dairy causes weight loss, right? That’s what the high fat diet crowd would have you believe, and they’ll tout this “evidence” as gospel to reinforce their near religious beliefs that going easy on fat is bad and that you should scarf it like the apocalypse is imminent because it’s a super food.
Except that saturated fat is not super food, or even particularly good food. Also, there are no super foods.
First off, when it comes to making conclusions, epidemiological (observational) studies are useless. They are simply “hypothesis generating.” What that means is we observe something, and then more rigorous, randomized controlled trials (real studies) are done in order to verify the hypothesis that’s been generated.
Often, epidemiological studies create “reverse causality.” Aragon described this potential confounding scenario: “There could be a pre-existing state of obesity that is causing a person to seek out low-fat products.” Low fat milk didn’t make them fat, they drink it because they’re fat.
It is just like the situation with consuming diet soda being correlated with more belly fat. There is no possible physiological mechanism for the diet soda to increase belly fat. Instead, it’s the case that people who already have obesity are more likely to drink diet soda. An added confounding variable is the possibility of a reward mentality – both with diet soda and with skim milk – that is created from consuming things that are lower in (or have zero) calories. They believe doing so earned them a treat, and those calories are compensated for via something higher in calories.
In fact, a 2012 meta-analysis of 33 randomized controlled trials (actual rigorous studies, not epidemiological studies) and 10 cohort studies published in the British Medical Journal examined total fat intake on body weight and determined that, “Lower total fat intake leads to small but statistically significant and clinically meaningful, sustained reductions in body weight in adults.” This was true for both adults and children, covering periods as long as eight years.
Calories are all that matter to weight loss, so any time someone says what amounts to “If you consume this thing that is higher in calories for the same volume, you’ll lose more weight” my bovine dropping detector goes berserk. It makes no logical sense, even when we consider the effect on satiety.
The argument is often made that by eating something with more fat in it you’ll be less hungry, but the evidence doesn’t support such a claim. As I showed in this piece, there are a number of problems with thinking that the minimally increased amount of satiety from consuming something higher in fat will be enough to compensate for all the added calories. The first is thermic effect: Protein burns a lot of its calories during the digestion process, carbs burn off a moderate amount, and fat burns off almost none at all. The other is caloric density. With fat being at 9 calories per gram (and the other two macros are 4 calories per gram) it’s a big wallop of calories in a small volume of food. There is also the fact that fat makes things taste great and can lead to overconsumption, as well as all the supporting research in the above link that shows fat is the least satiating macronutrient.
But you say that when you went on a higher fat diet it was more satiating? Aragon has an explanation for that. “People who say that usually increased their protein intake along with the fat, and protein is the most satiating macronutrient,” he said. Any study of the satiating effects of fat that don’t match for protein consumption is worthless, he says.
But there can be a problem with fat restriction, and that’s what people tend to replace it with.
A 2005 epidemiological study of almost 13,000 children asserted that “skim and 1% milk were associated with weight gain, but dairy fat was not.” I spoke with one of the study authors, Dr. Walter Willett of Harvard, and learned that it wasn’t exactly a fair comparison. It wasn’t just comparing higher fat milk with lower fat milk. Dr. Willett told me that the lower fat varieties had added in a lot of sugar through things like chocolate and strawberry flavorings.
So, yes, when you cut fat but replace it with a bunch of sugary flavors, that’s not going to help (even though sugar is not addictive and is not directly attributable to the development of type 2 diabetes). And Aragon stated that he was not aware of any randomized controlled trials that directly compare the effect of low-fat vs. high-fat dairy on body composition.
We Never Cut Fat
Another bit of misinformation spread by the high fat proselytizers is that people started gaining a lot of weight at the same time (1970s) the dietary health guidelines began recommending we cut back on our fat intake. They took this to mean that cutting fat makes people fat. Except, as I said, we never cut fat.
Yes, the recommendation was there by dietary guidelines to cut it, but a 2013 analysis published in The American Journal of Clinical Nutrition found that fat intake has stayed very stable across the decades. In other words, we never paid any attention to the recommendations.
So why did we get fat? Part of that is because of capitalism.
The low-fat recommendations led to an explosion in low-fat products that were instead high in sugar. When you keep your fat intake the same and then start scarfing high-sugar cookies called “SnackWells” because they’re low in fat, that isn’t going to help you lose weight. As the above analysis shows, fat and protein intake remained the same, but the consumption of carbohydrates – usually the highly refined variety – went way up. And this means that total calories went way up. And so, people got fatter.
Again: fat – specifically the saturated variety – is not a miracle macronutrient that makes people healthier or thinner by consuming more of it. Aragon stated that if people are recommending higher fat dairy for weight loss, then it would also make sense to recommend higher fat cuts of meat to do the same. But we’re not seeing any logical person saying that we should be eating deep fried chicken wings instead of skinless chicken breasts to achieve weight loss.
And that higher saturated fat isn’t always so healthy.
Dr. Nadolsky explained that, from a strict health perspective (and irrespective of effect on body weight), high fat milk or yogurt comes with few concerns. “Yogurt and milk have favorable metabolic effects that attenuate the fat.” So, if you’re able to drink high fat dairy or eat high fat yogurt and not have it contribute to a caloric surplus, then it shouldn’t be a problem.
The potential health problems come from too much butter.
“The more concentrated the fat, the bigger the problem,” said Nadolsky. “Butter has a lot of palmetic fatty acid which is know to increase LDL (bad cholesterol).” He explained that butter isn’t as bad as we once thought, but neither is it good for you. A modest amount can be fine, but he takes issue with exalting butter and the aforementioned “Eat Butter” proclamation on the cover of TIME. He’s also very much against putting huge gobs of it in your coffee.
How should you eat?
If you’re cutting fat from dairy as a way to cut back on total calories, the most important thing to realize is what the research does reveal: don’t compensate for this fat restriction with bad food choices elsewhere in your diet.
Earlier I said low fat milk consumption could very much be like diet soda consumption in that people of higher body weights may choose to drink it and that it can instill bad food choices in other areas because of a perceived earned reward. Dr. Willett said of my hypothesis: “I think that’s almost certainly correct.” He also stated that the poor choice of replacement calories from consuming lower fat foods and drinks could be unconscious.
Which means you must become more conscious of what you consume.
Cutting fat from things such as milk and yogurt is about cutting calories. And it only works if you don’t use it as an excuse to go off the rails in other areas of your diet. Willett says, “Focus on the quality of the diet over macronutrient ratios. It really does influence our caloric intake as well as the cardiovascular effects.”
Dr. Nadolsky is in favor of making lower fat choices such as skim milk. Part of the reason is that most Americans already get plenty of saturated fat in their diet; so, making small cuts here and there can be helpful. Another is that, “I’d rather get my fats from plants like nuts and olive oil,” Nadolsky said. “Those are proven to reduce cardiac events and improve health outcomes.”
Should you cut fat? The answer is that it depends. If its consumption is causing you to have a caloric surplus and unwanted weight gain, then yes, you should. If you’re putting butter in your coffee, then you almost certainly should stop doing that. If you have a desire to lose weight and cutting out bits of saturated fat here and there can be done and not lead you to compensating with the consumption of junk calories, then that can be valuable as well.
The most important thing in all of this is to stop believing the lionization of saturated fat. I will repeat: Just because it’s not as bad as we once thought doesn’t make it healthy, and more is certainly not better.
James S. Fell, MBA, writes for the Los Angeles Times, Chicago Tribune, Women’s Health, Men’s Health, AskMen, the Guardian, TIME Magazine and many other fine publications. His first book was published by Random House Canada in 2014. He is currently working on his next book, which is about life-changing moments.