A lot of popular advice is wrong. Many half-truths and misconceptions become “facts,” in spite of efforts at debunking them. But yet, doubt remains, and egregious fallacies still spread.
So let me share a few “urban legends of health” that I would like to see disappear once and for all.
Vegetarians Must “Combine” Their Proteins
This myth came from the book “Diet for a Small Planet,” by Frances Moore Lappé. The idea was that certain plant foods lack amino acids and must be combined with other foods that contain them. For example, rice and beans provide all of the essential amino acids.
In reality, the body doesn’t need to get a particular ratio of amino acids in one meal. It can get them throughout the day. Also, all whole plant foods contain the necessary amino acids as long as you eat enough calories. That is why you have to consume a broad range of plant foods, however you never need to combine the “proteins” in one meal.
The French Paradox
For decades, we believed that there was something in the French diet that protected them from heart disease. They ate a lot of saturated fats, yet had lower rates of heart disease. It was a “paradox.” Maybe it was the wine that protected them.
It turns out that there was no paradox after all. Dr. Greger writes:
“French physicians under-report ischemic heart disease deaths on the death certificates by as much as 20%, according to a World Health Organization investigation.
So, if you correct for that, then, France comes right back in line with the death versus animal fat and death versus cholesterol lines, with about four times the fatal heart attack rates as Japan decades after four times the animal fat consumption.”
Cardio is “Bad for You”
Although endurance sports like running or cycling, so-called “cardio,” are still popular, many people believe that they do more harm than good. The arguments I’ve heard against cardio are that:
- It’s not useful to lose weight.
- It can lead to reduced muscle mass.
- It can lead to chronic disease and mortality.
- It raises cortisol levels and increases inflammation.
All of these claims are wrong or out of context. When certain fitness trainers accuse cardio training of all those ills, they’re describing what happens when you over train.
Of course, doing lots of cardio without changing your diet is not going to help you lose weight. And running won’t help you train other muscles.
But claiming that “cardio is harmful” is irresponsible, as most people would benefit from aerobic training.
Any exercise releases cortisol and results in some degree of inflammation. But that’s how the body adapts and gets more efficient, stronger and healthier.
Studies have shown that endurance training decreases inflammation over time, and brings a lot of other benefits.
The truth is that some people take endurance training too far and over train to the point of damaging their health, which can also happen with cross-fit and weight training.
Cholesterol in Food Doesn’t Raise Serum Cholesterol
There’s a lot of misinformation about cholesterol because of the way many studies have been designed to deceive the public into thinking that eating eggs or other animal foods has no impact on cholesterol levels and heart disease.
The confusion comes from the fact that there is an upper threshold of cholesterol intake, above which additional cholesterol intake does not lead to further increases in cholesterol levels.
Every single study that showed that eating dietary cholesterol had no impact on blood cholesterol took groups of people who were already above this threshold.
If someone eats beef regularly, eating a few eggs on top of it will probably not affect their blood cholesterol. However, this doesn’t mean that the cholesterol in eggs has no impact.
When you take people with a zero cholesterol intake and add eggs to their diet, blood cholesterol values go up dramatically.
If you want to lower your blood cholesterol levels to healthy levels, you have to avoid all foods that contain cholesterol.
The China Study Has Been “Debunked”
The China Study – the book — summarized the findings of an extensive epidemiological study done in China, but also other types of studies that showed a connection between eating animal products and developing health problems, like cancer and heart disease. Denise Minger, a blogger who has no background in epidemiology, “debunked” the China Study. She made a convincing case, but when you look a bit deeper, no actual “debunking” took place.
Carbs “Make You Fat”
Health gurus love to sell you the idea that a particular food “makes you fat.” No matter how you dissect it, only one thing makes you fat: excess calories. How do we consume too many calories?
Generally by eating foods that are “highly palatable” — to use a term from the food industry. Those are foods that are rich and dense that don’t trigger our inner sense of satiety.
If “carbs” made people fat, then why are the thinnest nations on Earth living on a high-carb diet? If nuts, seeds or avocados made you fat, then why did all the research done on those foods show the exact opposite?
The problem is simple: we overeat! The solution is simple: eat foods that are low in caloric density. The combination of “fat and sugar” is the biggest culprit. Examples of this combination include peanut butter and jelly sandwiches, pasta in a fatty sauce, etc.
There is a good summary from obesity researcher Stephan Guyenet Ph.D.
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