Why Low Carb Diets Are More Effective Than Low-Fat Diets
Low carb diets beat out low-fat diets in every study I have seen. People can lose weight on low-fat diets, but these are the least effective diets and it’s time for them to be dropped. However, low carb diets aren’t superior to Mediterranean diets [1] when people are told to restrict their calories.
There are 3 possible explanations for why low-carb diets help us lose weight compared to low-fat diets.
By far, the most significant reason why people are losing weight on low carb diets is that they’re eating less.
You have to remember that people are reducing/eliminating the largest of the three macronutrient categories- larger than the other two combined (protein and fat). Telling people to go on a low carb diet is almost like telling people to go on a low food diet.
When you take out the most significant macronutrient group, food doesn’t taste as good as it did before, sapping our motivation to eat.
Low carb diets are known to also lessen appetite. Protein, specifically, is known to suppress appetite and low carb diets are significantly higher in protein. A study found that increasing protein intake from 15% to 30% makes people less hungry [2], which matches the dietary changes of a low carb diet.
Also, eating excess carbs in one shot can spike insulin and lead to hormonal changes that increase hunger, a property that fat doesn’t have. However, if you are moderate in your carb consumption, this isn’t an issue, but the fact is that most people aren’t (gulping down huge sodas with already carb-laden meals). To be moderate in carb consumption, you only have to eat less in general.
There also seems to be a significant percentage of the obese population that have less of an appetite on a low carb diet and they spontaneously eat less. An appetite-suppressing effect from low carb diets might in part be because these diets are also low in lectins and dietary lectins have the potential to cause leptin resistance in some of the population [3], thereby increasing hunger. Lectin sensitivity in the obese usually goes along with allergies and other immune imbalances.
Although not as significant as a reduction of calories, some of the weight loss can be explained by an increased metabolism. A study published in JAMA in 2012 found that metabolism does increase on a very low carb diet compared to a low-fat diet and a low glycemic index diet. [4] The low-carb diet compared to a low-fat diet resulted in a resting energy expenditure that was 67 calories per day higher and a total energy expenditure that was 300 calories per day higher, even though physical activity did not change during the study. Therefore, the low-carb dieters appeared to simply burn more calories per day than the other two diets. This seems to indicate a “metabolic advantage” of low-carbohydrate diets. (As an aside, the study found higher levels of CRP (a marker of inflammation) and cortisol excretion (not a good sign) in the low carb group and lower levels of thyroid hormones/T3, also not something I’d want. On the upside, leptin, PAI-1 and triglyceride levels were lower and insulin sensitivity and HDL levels were higher.)
So it’s possible that there are some biochemical changes from eating fewer carbs that result in some additional weight loss by increasing our metabolism or perhaps storing the calories differently. A study published in 2007 speaks about a variety of possible metabolic changes that could change weight, without a calorie change.
However, my contention is that consumption of carbs isn’t the source of our weight issues, even if low-carb diets can be used as a tool to reduce weight. This is supported by observations of the Japanese and the fact that a Mediterranean diet results in similar levels of weight loss even though there’s plenty of carbs in the diet.
To illustrate my point, statins are highly effective at reducing cholesterol, inflammation and heart disease risk. But it would be misleading to say that we get heart disease because of a deficiency in statins. So all because a therapeutic tool can help some of us, it doesn’t mean that the source of our issues, to begin with, are related to that tool.
So What’s The Secret of The Japanese?
The Japanese focus on eating less of everything without differentiating between carbs, protein, fat or healthy food.
According to one source, the Japanese eat 25% fewer calories than we do in the US.
There’s no fad diets or low carb diets in sight. They all eat high carb diets with lots of refined rice.
The Japanese have a culture of restraint and people take care not to gain weight from a young age. It’s a tradition to eat only until they’re 80% full. They eat less, exercise more and have smaller portion sizes. And if you do get fat, no one will spare you from disgrace there – they will fat shame you [5].
There are also strong social norms that discourage eating while at the desk, in school, walking, or taking the train, as well as a family culture in which the wife prepares three meals a day for her husband and children. They don’t snack much either.
They don’t eat/snack after supper. Aspiring sumo wrestlers who are trying to gain weight purposefully eat at night [6].
To sum it up. the Japanese have a healthier relationship to food and have healthy habits in general. It’s part of the culture. They probably laugh at our diet and low-carb theories.
In a study from Pennsylvania State University, researchers served women meals that were 25% smaller than average and contained 30% fewer calories according to the principles of energy density. They ended up eating an average of 800 calories less per day – all without even missing the extra food.
This is something the Japanese grow up doing. They have a different conception of what a normal portion size is.
People eat up to 45% more food when served bigger helpings, according to scientists from the University of Illinois, Urbana-Champaign. When asked to identify what determines the size of the portions they eat, nearly seven out of 10 respondents in a recent American Institute for Cancer Research (AICR) survey claimed that the amount they were accustomed to eating was what determined the amount of food they placed on their plates.
As you can see below, within America, we lost sight of what normal portion sizes are and this correlated with the obesity epidemic to a large degree. Some stores sell small glass coke bottles that are reminiscent of the size they used to be. Now, the bottles have ballooned and when we buy it, we finish like to finish it.
Even the low carb study that recently came out showed that people who lost weight reduced their caloric intake [7].
So while it may be the case that eating fewer carbs helps curb some people’s appetite, the reason they’re ultimately losing weight is that they’re eating less.
Also, I am working on an article that is focused on the biology of appetite and why we overeat. This post is more geared around nonbiological causes.
Testing The Overeating Theory
Most people don’t gain weight overnight… it happens slowly, over years and decades.
But the rate is uneven throughout the year and spikes dramatically during the holidays, a time when people tend to binge on all sorts of delicious holiday foods and eat much more than their bodies need.
The problem is that sometimes people don’t lose all the weight back. They might gain 3 pounds but only lose 2 after the holidays are over, leading to slow and steady weight gain over time [8].
In fact, a large percentage of people’s lifetime weight gain can be explained just by the 6 week holiday period.
The graph below gives us a more complete picture. As we can see, our increased caloric intake matches up well with our obesity rates.
According to studies, this increased calorie intake is more than sufficient to explain the increases in obesity [9].
The social environment is another factor that determines calorie intake. For example, eating in a group can dramatically increase the number of calories consumed.
According to one paper, eating a meal with several people can increase calorie intake by up to 72%, or 310 calories in a single meal [10].
There are also studies showing that people tend to eat more during weekends [11].
Aspiring sumo wrestlers who are trying to gain weight always eat with others in a social atmosphere [6].
Exercise and Weight Gain
A lot of people blame obesity on decreases in physical activity, that we’re just burning fewer calories than we used to.
Although leisure-time physical activity (exercise) has increased, it is also true that people now have jobs that are less physically demanding.
The graph above shows how people are now burning around 100 fewer calories per day in their jobs, which may contribute to weight gain over time.
The Japanese expend significantly more calories than we do. It seems like people are afraid to walk even a few blocks in the US. We love our cars.
We’re Addicted to Eating, Not Food Itself or Specific Macronutrients
A recent study has shown that many of us aren’t addicted to food per se, but rather we’re addicted to “eating” [12].
Most of us eat even when we’re not even hungry. Sometimes we eat when we’re bored or if we’re with friends and they’re eating or if we’re at a gathering and there’s food all around. Imagine standing at a celebration looking like a dork not eating.
Our culture encourages eating. We are served humongous portion sizes and there’s no restraint in sight. We are bombarded with commercials that tell us we need to drink more milk to grow strong bones. Mothers constantly push food on us even when we say we’re full. We’re surrounded by food as well.
We’re also stressed like hell, which increases appetite that we don’t end up burning off because we’re in offices. We snack to alleviate emotional anxiety.
The blogosphere has us believe that we are deficient in various micronutrients, so we feel we need to eat various foods, lest we are deficient.
The Right Diet For Us
The right diet for us is one that will allow us to eat less. If you can eat less following a low carb diet in the long term and you are satisfied with it, then that’s the diet for you.
The ultimate answer to weight loss is people need to find a diet that they can stick to for the rest of their life and that allows them to eat less in the long-term.
Preventing Weight Gain May Be Different Than Losing Weight
I want to acknowledge a point that is missing thus far from this post: not gaining weight isn’t the same as losing weight once someone is obese.
The problem in the US is, first we get fat and then once we realize we’re 50 – 100 pounds overweight, we decide to lose the weight. Guess what? Losing weight is much harder than not gaining it, to begin with.
I believe there are truly many people that can’t lose weight no matter what they do and it’s not an issue of willpower.
When you get used to being at a certain weight the body alters your set point and trying to lose weight is like fighting an uphill battle for many. I’m sure this depends on genetics, but some people can put all of their motivation into losing that weight, with little success.
Another part of the equation is that our bodies are capable of using energy more efficiently, which leads some people to have to reduce calories to an uncomfortable level. This means that someone can be obese and when they try to cut their caloric intake, they feel weak, cold and constantly hungry.
According to researchers, our muscles can make us more efficient so that someone would have to eat 20% fewer calories than other people.
Based on this video and our own observations, we must acknowledge that this is a potential problem for many.
Obesity is like a chronic disease. Like most chronic diseases, it’s easier to prevent than cure once you have it. Once the disease takes hold, there’s a new homeostasis and it’s hard to reverse. Many times people do cure their full-blown conditions, but it’s an uphill battle.
This is why I am working on a post regarding the biology of obesity, which will allow me to write another post about how various lifestyle factors interact with our biology.
I am sure we are to see contradictions with this post, however. The point of this post isn’t to completely discredit every theory out there but to put things into perspective. My point is to show you that if there is a difference, it’s not a massive one. Sometimes, if you have a lot of insignificant causes, it could sum up to be significant.
With all this said, it’s important to realize that low carb diets are not a cure for obesity. Maybe it could help a little for some, but it isn’t a cure, as some will have you believe.
Many people who go on low-carb diets don’t get the success they want. According to the Bullshitexec, 70% of people on a low carb cruise he went on were obese.
The Role of Lectins
There’s a percentage of the population that is obese and also afflicted with autoimmune issues. Such people include the Bullshitexec, ThePaleoMom, and others in the paleo community.
Lectins cause leptin resistance in a subset of the population [3]. In these people (and the clients I’ve seen), Th2 dominance seems to occur, with an insatiable appetite when lectins are consumed. Read more about lectins.
In other people, lectins cause the opposite problem and make them extremely thin. These people are usually Th1 dominant.
I don’t consider this a carb issue, but rather a lectin issue. Lectins happen to be high in carb-rich foods, so this can surely cause people to mistakenly believe that carbs are the issue rather than lectins.
Admittedly, if I haven’t afflicted with lectin sensitivity myself, I’d probably think it’s BS.
It’s possible that some people aren’t lectin sensitive but have hunger issues when they eat lectin free carbs (they’d need to consume pure sugar or glucose to test this theory). If this is the case it’s probably a small percentage of the population.
Still, while lectins might be a factor for some in weight loss, it’s hard to conclude that it’s very significant for the population as a whole, since the Japanese eat lectins, too. Europe and France have been consuming grains throughout the 20th century (for millennia) before the obesity epidemic hit.
