Is Fat Good? Thoughts behind low carbohydrate, high fat diets.

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If you had told me 6 months ago that a low carbohydrate, high fat (LCHF) diet can hugely benefit one’s health and that it has the potential to change modern medicine as we know it, I would probably have laughed in your face. Fast forward to now, and after reading numerous books and articles on the topic, it’s safe to say my view on the topic has changed a great deal.

A Brief History

Pre World War Two, the prescribed diet for weight loss was a diet that heavily restricted carbohydrate and replaced your food intake with mainly fats and protein (usually more fat than protein). Some of the first documented success of this diet being effective in weight loss dates back to the 1800’s and the story of a man named William Banting. Banting was an English undertaker, who despite trying numerous diets, could not seem to lose weight (or corpulence, as it was described at the time). He was then prescribed a LCHF diet by the physician Dr. William Harvey, who had become aware of such a diet through the work of the legendary French biochemist Claude Bernard. Bating then wrote an open letter to the public, containing information about his diet and how much weight he had lost due to it. The rest, as they say,  is history – well at least until Germany invaded Poland.

 Fast forward to the 1960s and cue Ancel Keys, an American Biochemist who decided to disregard a large amount of the research done previously with respect to weight loss diets. It was common for many American scientists to shun previous European research, particularly from Germany and Austria, after WWII. Keys put forward some very, very suspect data (he basically picked out the data that would support his theory aka – cherry picking) that depicted a nice linear graph to ‘illustrate’ a positive correlation between fat intake and heart disease. From this data, Keys then championed the ‘lipid hypothesis.’ The Lipid Hypothesis basically says that too much dietary fat was the cause of heart disease, and thus should be restricted in the diet. This was the catalyst for the healthy food guidelines (the pyramid and derivatives of), despite very little evidence on which to support the hypothesis. From there Keys got his picture on the front of Time Magazine and quickly became regarded as one of the best ‘experts’ in the field of weight loss.

Ancel Keys on the cover of Time Magazine in January 1961

Dr. Atkins – Ahead of his time or just good at looking back at the past?

In the 1970’s Dr. Robert Atkins realised that despite the American public following the eating guidelines that stemmed from the original lipid hypothesis, Americans were fatter and more prone to heart disease and diabetes than ever. Despite very strong criticism from many in the medical community at the time, Dr. Atkins came up with the Atkins diet, which severely restricts carbohydrate intake and encourages eating as much fat and protein as you desire. There is no calorie restriction (calorie restriction doesn’t work –  if you want to lose weight and keep it off) and relies on the body’s homeostatic mechanisms to regulate your weight and appetite. This diet has yielded amazing results for 1000’s of obese people and still does to this day.

One of Dr. Atkins’ early books

Low Carbohydrate Diets – The Now

Low Carbohydrate diets have been thrust back into the spotlight through the work of individuals such as Tim Noakes, Gary Taubes and Peter Attia, just to name a few. All have meticulously read through the research relating to weight loss and cardio-protective diets, and have found virtually no good evidence to support low-fat, high-carbohydrate diets being efficacious in promoting weight loss and preventing heart disease and diabetes. The mainstream medical and health community is starting to take notice – however, this is occurring slowly. Why? I feel it really is just an inconvenient truth, literally too far against the grain (pun intended), as it goes against everything that has been taught in modern, conventional western medicine for the last 60 years.

So, how do low carbohydrate diets actually work?

Eating fat, makes you fat, right? Wrong. Eating too many carbohydrates (more than your body can use and store as glycogen) appears to make you fat. Human weight and hunger regulation is an incredibly intricate and cascading process, requiring many enzymatic and hormonal interactions and goes way beyond the length of this post, but the main effect of a LCHF diet is to decrease the amount of insulin in the blood stream.

Insulin is a hormone released in response to glucose in the blood stream (glucose is what carbohydrate is broken down to by your body). Insulin has many functions (good and bad), but in this instance we are mainly concerned with its effect on the storage and usage of carbohydrate. Insulin stops blood glucose levels getting too high; to do this it facilitates the transport of glucose into your body cells. The first port of call is for carbohydrate to be stored as glycogen, the body will only store around 300-500g of glycogen (depending on your body weight), so once this level as been reached the excess carbohydrate will mostly be stored as fat. Therefore when there is more carbohydrate than can be stored as glycogen, the excess will be stored as fat.

Insulin also promotes the usage of carbohydrate for energy at the expense of fat, thus preserving the body’s fat stores. So, the thought is, that less insulin in your bloodstream, the less fat storage and more fat burning.

Furthermore, ingesting Fat and Protein will keep an individual fuller for much longer, as opposed to carbohydrates. This occurs through the release of satiety hormones such as Cholecystokinin in response to fat intake. This decreased hunger will allow a person to go longer between meals and indirectly lead to the consumption of fewer total calories.

What do I eat if I’m not eating Carbohydrate?

Simple: Fat and Protein, with more fat than protein. A strict LCHF diet will limit carbohydrate to less then 50 grams per day, but this number can be so variable from person to person. On a LCHF you should aim to get around 60-80% of your calorie intake from good fat sources. Some people get the wrong idea when they hear they can go and eat lots of fat and immediately think McDonald’s binge – this couldn’t be more wrong. We are talking good wholesome fat and protein from animal and plant sources. Staples of a low carb diet include, low-carbohydrate vegetables, fatty meats and fish, eggs, nuts and avocado, just to name a few.

Eggs are a staple of a LCHF Diet

Should I go low-carb?

Not an easy question by any means. It depends on so many variables, and again, is beyond the scope of this blog post. If you are keen on a change of diet, I would very much suggest trying it, but I would strongly, strongly recommend doing a lot of research and talking to people in the know before starting out. Do not go in blind.

People who are (pre)diabetic, have a family history of diabetes or cardiovascular disease or who are trying to lose weight may significantly benefit from this diet.

Athletes and Low-carb Diets

Should or even can athletes go low carb? Maybe. Again it depends on so many variables – sport, intensity, time of the year, individual physiology, etc., etc. One thing I will say though is that athletes, especially those who are concerned with their body composition, should not be scared of eating fat, it most likely won’t make you ‘put on weight’ and will probably benefit your training and competition – after all, our red (oxygen carrying) and white (immune) blood cells are composed of derivatives of fats and cholesterol, along with every other cell in your body. Dave Zabriskie, an elite professional cyclist, recently changed his diet to contain less carbohydrate and more fats, which has actually improved his performance. However, most athletes will not have to restrict carbohydrate by as much as those relatively sedentary individuals who have, or are at risk of, diabetes and/or heart disease.

 

Note: Some of the points put forward in this post may not sit well with some individuals, but I would suggest that you read it with an open mind. I very much welcome any criticism to these ideas, but stress the point that I have attempted to fit what is literally an entire text book worth of information into a concise blog post. I have included a list of recommended readings on the topic below, which I very much hope you have a read of.

Recommended Reading

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