Why the Low-Carb, High-Fat Craze is Unfounded.

The most recent craze within the nutrition and health industry is undoubtedly the “low carb high fat” (LCHF) craze. No longer is fat the bad guy, but now it’s carbohydrate: particularly sugar. Self-proclaimed nutrition experts are promoting this extremist diet, in the hope to gain followers, and often have products linked in with the success of their campaign such as books, supplements, or nutritional services.

(Before I start, do you really think it’s a good idea to trust someone’s nutritional advice when they have an entire book promoting an extremist diet? Realise that they have pinned themselves down to some extent. They have a reduced capacity to change their opinion despite what the science says, as they have financial ties to integrity in their position….)

Firstly, a look at the food pyramid:

From reading my previous articles/posts, you should be able to assume that I’m not in favour of labeling foods good or bad and so dislike any form of food pyramid. HOWEVER, I simply can not stand when people bash the current food pyramid, which if you didn’t know, pretty much promotes high carb low fat, and say that it needs to be refurbished as the recommendations are wrong, and use the current obesity epidemic as proof that it doesn’t work. Let me ask you, do you actually believe that the current overweight/obese population ate high carb low fat diets to end up where they are? Or did they eat high carb, high fat, low fibre, (hence) high calorie and not exercise enough? It is strikingly obvious to me that it is the latter.

The food pyramid doesn’t work because people don’t follow it, not because the recommendations themselves are terrible. I agree that the pyramid’s recommendations are not perfect (and doubt any pyramid could be “perfect” for the entire population), but they’re definitely NOT the cause of the obesity epidemic! In fact, the “blue zone” populations (oldest living people in the world) eat a diet which is abundant in carbohydrates without containing excessive calories. This type of diet is similar to what the pyramid recommends.

So, are LCHF diets ultimately superior for weight loss, health, and longevity, as some claim?

Rather than cherry-picking journal articles, I will provide a few recent reviews on the topic. Systematic reviews and meta-analysis of the research are usually the best, unbiased sources of up-to-date information around nutrition (and other topics in science). They analyse and summarise the trends in the research. The review by Johnston et al. (2014), examined the research on weight loss in overweight and obese adults following different style diets. Their was no difference in weight loss between low fat and low carbohydrate diets. Another review by Naude et al. (2014), revealed that in obese subjects either following a low carbohydrate diet or a balanced diet, weight loss was the same between groups, as well as improvements in health markers such as blood pressure, LDL, HDL, total cholesterol, triglycerides, and fasting blood glucose. And another huge review by Hu et al. (2012) comparing low carb to low fat  concluded “Reductions in body weight, waist circumference and other metabolic risk factors were not significantly different between the 2 diets. These findings suggest that low-carbohydrate diets are at least as effective as low-fat diets at reducing weight and improving metabolic risk factors.” 

Johnston et al. (2014) recommends practitioners to prescribe a style of diet which their clients prefer & as such have a higher chance of adhering to long term. Whether it be low fat, low carbohydrate, or moderate intakes of both macronutrients, the key for long term weight loss is a caloric deficit over a long period of time.

If the research doesn’t show a supremacy of LCHF, why are there so many great anecdotes by people using LCHF?

This great chart by Antonis Damianou of Smart Training and Flexible Dieting illustrates it quite nicely.

Simply put, an initial drop in water weight caused by low carbohydrate intake, results in a positive feed back loop whereby the person believes fat loss is occurring rapidly, meaning that short term adherence to the diet is increased.  There is also a big confounding variable: protein. Foods that are often promoted in LCHF diets such as fatty meats, whole fat milks, nuts, cheeses, eggs, etc, are high in protein. This elevation in protein intake has multiple positive effects for weight loss and body composition: higher thermic effect of food (protein requires more energy to digest/absorb than most carbs or fats), increased muscle gain (or at least increased muscle retention during weight loss). Higher satiety (feeling of fullness) also occurs, resulting in reduction in total calorie consumption, resulting in a caloric deficit and fat loss. The high satiety per calorie induced by LCHF diets due to the inherently high protein and low sugar content is the main upside of this style of dieting in my opinion.

Ok, so this chart shows LCHF diets can work for fat loss?

They absolutely can and do work for fat loss. At least for the short term. The general push for the population to consume less “refined” foods and more “natural/whole” foods is good in general. It will improve protein intake and reduce overall caloric intake, which would improve population health. However, the recommendations often made by LCHF gurus to the general public are extremely misleading. Copious amounts of coconut cream, butter, or lard, or anything high in fat and low in protein for that matter, are not going to be extremely helpful for fat loss. Foods high in fat and low in protein and fibre can lead to over-consumption of calories more easily than foods high in carbohydrates and low in protein, as discussed in Chambers et al., 2015. Feelings of satiety and weight loss can be achieved in other styles of dieting by eating a diet high in fibre and protein (Chambers et al., 2015) without excluding any food groups. Read my article about this here.

In my opinion, the main downside of LCHF diets is how unsustainable they are. If you can see yourself eating low/next to no carbohydrates for the rest of your life, then go ahead – try it. But why would you? For no additional benefit to the LCHF approach compared to a moderate approach, I for one (and I’m sure most of you), would rather still incorporate higher carbohydrate, tasty foods into my diet while achieving optimum results. With appropriate calorie, fibre, and protein control, you don’t have to exclude any of your favourite foods. Read this to learn more.

Side note: An aspect the LCHF approach I’m a bit confused about is, what happens when weight loss stalls? Do you eat more fat? With flexible dieting it’s pretty simple, increase activity or reduce caloric intake slightly. But considering a lot of LCHF advocates don’t even track calories or recommend it, I wonder what adjustments are made to “keep the ball rolling”? Hmm…

Summary

Why must their be “good foods” and “bad foods” and why do we have to demonize either fat or carbohydrate? Why does it either have to be high carb, low fat, or low carb, high fat? Where’s the middle ground?

What about a moderated approach to include all macronutrients in reasonable quantities according to preference, without having to shy away from any foods/food groups in particular? In my opinion that is more sustainable. I think extremist style diets are promoted simply because the public will listen, and so there is money to be made. The average Joe doesn’t want to hear “everything in moderation” or “calories are of number one importance when it comes to weight loss”. That’s boring. They want to hear about the most recent/trendy diet, no matter how sustainable.

If you are interested in inquiring about my online nutritional services whether it be for general fat loss and health, or sport-specific, please contact me here.

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The following articles are great reads and I highly recommend them:

Eric Helms “The Myth of Good and Bad Foods”

Layne Norton “The Science of Sugar and Fat Loss” 

Joy Victoria “Your Problem with Sugar is the Problem with Sugar” 

James Krieger “Good Calories, Bad Calories: The Mythology of Obesity, or The Mythology of Gary Taubes?“

JC Deen “If You Want To Lose Fat, and Keep It Off, Don’t Fall For The Low-Carb Trap”