Over the years, our society has discovered new dietary insights. Each new discovery results in a shift to a different and highly popular diet coined with its own name. Currently, some of the most popular diets are Paleo, Mediterranean and the old faithful Adkins diet. Moving past the 1950’s, as America continued to prosper, our waistlines likewise continued to grow. During the 1980’s and 1990’s it was reasoned that since our growing waistlines were composed of fat, the logical solution was to reduce fat consumption, thus the popular diet for that time was called low-fat.

Strangely, however, waistlines continued to grow. The popular theory for the low-fat failure is that when people went on a low-fat diet, they compensated by increasing carbohydrates. Further, it was noticed that if carbohydrates were severely restricted, one could lose weight, even while consuming lots of fat. So, the low-fat diet was deemed a fad and carbohydrates became the villain and sugar was placed at the very top of the list as the most fattening thing to eat. Low-carb-high-fat then took the lime light with the consensus that fat doesn’t make you fat; it’s carbohydrates that make you fat! A Google search for 1990’s low-fat craze illustrates the widespread embracing of that theory.

So, today, fat is the in thing. By popular opinion, fat could almost be labelled a super food. Typical advice is to seek out all the "healthy fats" you can find.

The Confusion
The geek in me, however, has some issues with that logic:
1 – Eating more fat to lose fat seems like a mathematical violation. That’s like saying 2+2=1.
2 – Carbohydrates do not readily convert to fat (More on that later).
3 – The composition of fat is already stored energy, thus it needs little to no processing for storage in one’s fat cells.
4 – Personal experience, biological studies and observation of others.

Well, this all seems just crazy… This should mean just the opposite of what happened during the low-fat craze, but sure enough; people can lose weight on the low carb high fat Adkins diet and perplexingly, people can gain weight eating carbs. So, how does that happen? Why did the low-fat craze of the 80’s and 90’s fail? And, why did I lose 40 pounds upon changing to a high carbohydrate, low-fat diet?

The Low-Fat Craze Failure
Well, as it turns out, the low-fat craze was never low-fat at all. It was low-fat in name and marketing, but it was anything but low-fat. The problem was the marketing. It was, and still is, considered that 35% dietary fat calories is low-fat. In metabolic reality, however, 10% is the low-fat threshold (more on that later). During the low fat craze, everything was advertised as low or reduced fat without regard to the actual content. A good example is Vegenaise. Vegenaise was first introduced in the early 70’s, just as the vegetarian low-fat interest was starting to gain speed. The label advertises "REDUCED FAT". 

In reality, however, it is not low-fat at all. Not even a little bit. The nutrition facts label lists total calories per serving as 50 and total fat calories as 50. Mathematically, that is 100% fat. So, what was the fat reduced from?

The Details
As a Type-1 diabetic, I have the inability to produce my own metabolic control hormone - insulin. Thus, I must measure and inject it myself. The measuring and logging of my food, activity and insulin doses provides a near direct metric of metabolic efficiency. This metric very clearly reveals that fat is a powerful metabolic suppressant called Insulin Resistance, which impedes the conversion of glucose into energy. From this metric, it was found that peak metabolic efficiency occurs with fat calories between 5 and 10%.

The lower the fat intake, the less insulin resistance, the less blood-insulin is required and the more efficient glucose converts to energy. 10% fat is the knee in the curve where metabolic efficiency takes a sharp increase. Above 10% fat and insulin resistance starts a steep increase and metabolic efficiency a steep decline. Dr. John McDougall recommends 7% or less. This metric also reveals the fat / carbohydrate relationship.

The Fat / Carbohydrate Relationship
The simple sugar, glucose, is biology’s fuel. It is a hard requirement – on the same level as oxygen. All animals require blood-glucose and nature’s biology employs amazing methods to ensure its supply, regardless of the animal’s diet.

Carbohydrates quickly and efficiently convert to glucose supplying energy on demand. Fat is biology’s energy storage, consisting of the highest calorie density of anything edible. Fat can be converted to energy, but it is a lengthy multi-stage process which lags demand (more on that later). Therefore, when carbohydrates and fat are ingested together, as in a pastry, burger, anything fried, etc. the carbohydrates quickly convert to sugar (glucose) which readily converts to energy, supplying your fuel needs, and leaving all of the fat to be stored.

Carbohydrate conversion to fat, de novo lipogenesis, is a rare occurrence, only taking place when the fuel (glucose) intake severely overwhelms the energy demand. Biology’s response is to elevate the "burn-rate" in order to burn off the excess glucose; a process known as facultative dietary thermogenesis. This can be recognized by feeling warm or being "hot-natured". Consuming enough carbohydrates or sugar for de novo lipogenesis to occur is difficult to an unlikely degree, but even if it does, the conversion efficiency is less than 30%.

With restricted carbohydrate consumption, fat must be converted to energy to fill the fuel needs gap. The fat to energy process, however, is very complex and slow; generally lagging requirement, making one feel tired. As a fuel, however, fat can only serve as a supplement. Glucose is always the primary fuel – one cannot live, even for a very short time, without blood-glucose. Note that if fat were a good fuel, having plenty of it in store should be a good thing for extreme high energy, endurance athletes, however in reality, such athletes carry a very low body fat content. Notice how all of the ultra-marathon competitors in this Google search are very lean. As for non-athletes, here is a video comparison between high carb, plant based verses low carb promoters.

This relationship has been widely misinterpreted resulting in many misconceptions, including falsely blaming carbohydrates for weight gain. The misconceptions have further provided an absolute marketing bonanza. For example, when the 100% fat Vegenaise (mentioned above) is added to a baked potato or spread on a sandwich, etc., all of the Vegenaise will be stored as fat, while all of the carbohydrates will be burned as energy - but it’s the carbohydrates that get the blame. As Dr. John McDougall says, The fat you eat is the fat you wear. Indeed fats are essential. They are required as building blocks for our biology; however, fats are the most concentrated of all food items, so a little bit goes a long way. In fact, unless one is starving, it is virtually impossible to be fat deficient.

Simply put; carbs alone (less than 10% fat) will not add any weight, indeed it will restore normal lean weight, add muscle definition, energy and strength. Carbs with greater than 25% fat adds weight. Fat alone does not add weight, but reduces metabolic efficiency.

It is important to understand that metabolic efficiency affects every organ and every function of one’s body, from the immune system to muscle movement to growth/repair to mental processes – everything involved in being alive. Metabolic efficiency and insulin resistance are inversely proportional. As insulin resistance increases metabolic efficiency decreases. A few symptoms of insulin resistance are aches and pains, inflammation, arthritis, joint disorders, feeling old (at any age) and feeling tired to name just a few. Typically, these effects are dismissed as "normal" due to the deceptive timing of insulin resistance. Carbohydrates are considered bad because of the blood-sugar spikes that occur shortly after consumption. Unfortunately, it is never noticed that this only occurs with insulin resistance. It is never noticed because the fat ingestion to insulin resistance takes 24 to 48 hours, but then lasts for weeks. Ingesting more fat within those weeks adds more weeks, becoming months, becoming years, becoming a lifetime, becoming the standard.

Diabetes Misconception
At social events, where snacks are served, I am often offered a pastry, cookie, etc. then the person suddenly remembers that I am diabetic and apologizes for the "off-limits" sugar content. I always try to point out that sugar is not off-limits; it’s the fat content that makes sugar a problem. The chances, however, of any snack containing less than 10% fat are very unlikely. But, if I know that the offered snack contains less than 10% fat, I happily partake – even if the sugar content is shamefully high. :-)

Please understand that this writing is not medical advice and that I am not a medical professional in any capacity. This writing is only to share my experience and what I have learned from it.

Nothing in life is more inhibiting or debilitating than the belief; "I Can’t."
Nothing in life is more freeing, enabling and successful than the belief; "I Can."