Leaving the research into longevity aside, I want to revisit the link between intermittent fasting and weight loss. This post is more of a personal experience that will help you conquer weight control without any of the common side effects of dieting.
Many of you who know me will realize by now that overcoming the rebound effect is possible. I have done it, and so have many of my friends. Intermittent fasting works, but you must understand how it changes your metabolic system so that you do not sabotage it.
So what do I mean by sabotaging this miracle diet? Let’s start from the beginning and explore a few concepts to help you understand what not to do.
How to Lose Weight on a Ketogenic Diet
Unless you have been living under a rock for the past few years, you have probably heard about some form of dieting that emphasizes low carbohydrate intake. The purpose of these diets is to bypass the body’s signaling mechanism for fat storage. The hormonal signal to store fat no longer works when insulin levels remain low.
Humans cannot survive very long without insulin. Ask any type 1 diabetic, and they will explain to you what they have to go through to stay alive. A long-term user of insulin injections will begin to notice lumps of fat developing around the areas where injections of insulin are administered. With an insulin shot, excess glucose in the blood is quickly converted into fatty acids and absorbed into the neighboring fat cells.
Fat as the Primary Fuel
So how does this help us understand weight loss on a ketogenic diet? The answer is simple: lower carbohydrate intake means lower blood glucose levels. If glucose levels remain at a non-toxic threshold, insulin levels remain low and the body’s fat storage signaling mechanism is bypassed.
In fact, you can pretty much eat all the fat you want to eat for fuel without gaining any weight because the hormonal signal to absorb the fatty acids is off. Your liver begins to break down fatty acids and produce ketones and the necessary glucose to keep your body fueled, and any excess dietary fat is excreted without being metabolized.
When fat intake is low, fatty acids will come from fat cells and you end up losing weight. This negative fat flux becomes easier to accomplish when your liver is adapted to fat as the primary fuel. Beyond the short-term adaptation of 5 weeks, I and others have also reported a long-term adaptation after 1 year of doing this. These days I can engineer a state of nutritional ketosis after 1 day of eating a large high-carbohydrate meal and 2 days after having a continuous 24-hour period of a high-carbohydrate diet.
Carb Cycling & Intermittent Fasting
In the summer of 2016, I made the switch from a ketogenic diet to intermittent fasting. I was in nutritional ketosis for two years at that point. From time to time, I did cycle into a high-carbohydrate intake for 1 or 2 days per week. However, I found that my weight was quickly rebounding in favor of fat storage when I increased the frequency of carb-cycling.
My insulin sensitivity was so high that I could no longer tolerate the modern high-carbohydrate diet. It was amusing to see blood sugar tests reading in the low 70s 1 to 2 hours after a high-carbohydrate meal. My body overreacted to the insulin to such an extent that physical and mental fatigue quickly took over. When I did have a high carbohydrate meal, I felt bloated and began to sweat profusely. It was clear that my metabolism had changed.
The other observation I have is the effect of carb cycling on sleep patterns. If I have a high-carbohydrate meal before sleep, my sleep is disrupted. The excess sweating I mentioned earlier is my body trying to metabolize the carbohydrates with an urgency that prevents a normal sleep cycle. This simply does not happen on a ketogenic diet because there is no urgency in metabolizing fat. If I have a high-fat, low-carbohydrate meal right before sleep, my sleep is not disrupted.
Intermittent Fasting Triggers Ketosis
As time passed, I began to fine-tune the frequency of carbohydrate intake and fasting cycles. There is no formula that fits every person here. There are a lot of variables: your age, genes, level of insulin resistance, stress levels, initial weight, level of activity, sleep patterns, and even the weather. I can write a separate article on each of these factors, but the important thing to note is that you will need to experiment with ketosis to understand how your body handles it.
I was already adapted to a low-carbohydrate diet, and the transition into intermittent fasting was effortless. In fact, I found that a state of ketosis suppresses hunger, and that makes sense because an adapted liver can efficiently generate all the ketones and glucose that the body needs from fat stores, even when dietary fat intake is low.
In the same way that the liver adapts to a low-carbohydrate diet by producing ketone bodies, it also adapts to intermittent fasting by facilitating nutritional ketosis, which provides the nervous system with the fuel needed during the fasting phase.
Some forms of intermittent fasting regimens will allow dietary fat intake during the fasting phase, especially when intermittent fasting cycles are longer. One such variation that I previously wrote about is the bone broth diet. These diets work in the same way by triggering nutritional ketosis.
How I Overcame the Rebound Effect
The fine-tuning I made over the years was done with frequent feedback from various devices that measure ketone and glucose levels in the blood. In time, I needed less feedback from these instruments, and I could detect the presence of excess carbohydrates in the food I ate.
Let us say, for example, that I order a creamy soup in a restaurant, and the chef decided to save money on a thickening agent by using corn starch as opposed to cream. Immediately after the meal, I begin to sweat more than usual. Two hours after the meal, I become lethargic and get brain fog. This is the same feeling that people get when they first enter nutritional ketosis. In one instance, the liver was too busy cleaning up the excess glucose to produce ketones; in the other, the liver has not yet adapted to producing enough ketones to fuel the nervous system.
I also detect sugar in my food to a high-level of accuracy. If it is in the dressing on a salad, I can taste it as being too sweet. In fact, my sensitivity to sugar is such that I have been psychologically conditioned to dislike the taste of sweet food. From the various research that I have come across, sugar is an addiction that can be overcome. It can take up to 1 year to truly appreciate how much of the joy you get from consuming sugar is due to the addictive properties dietary glucose and fructose.
Do Not Binge on Carbohydrates
All diets that work to increase the negative fat flux change your metabolic rate. This is not to say that you burn fewer calories because you can end up burning more calories being more active and energetic on a lower metabolic rate. This is the metabolic efficiency that ketogenic dieters experience.
There are several advantages to intermittent fasting over a continuous ketogenic diet. One is that you can reintroduce some nutrient-rich foods that happen to be high in carbohydrates without giving up the benefits of nutritional ketosis. The other is the flexibility in food selection that allows for the occasional socially-motivated “cheating” that dieters often take to mean binging. There is no easier way to sabotage your intermittent fasting than to binge on carbohydrates during the refeeding periods.
Binging on carbohydrates works to increase insulin resistance, increase the severity of hunger even when the fat flux is positive, and it does not help you get rid of the addiction to easily-absorbed refined carbohydrates. The key to making it work is to utilize the refeeding period to load up on nutrient-rich food that would typically kick you out of ketosis. See, for example, the list of food items in the Fasting Mimicking Diet and the list of food with high polyphenol content.
Eating strategically works to better your health and delay the aging process. Weight loss is one ancillary benefit, but it gets a lot more attention by dietitians as the ultimate end in and of itself. When you adopt a healthier pattern of eating, your weight reverts to its natural state. Your genes will still play a role, but it is the difference of having a younger body that is able to metabolize all the junk you are eating and an older one that is no longer capable of metabolizing excess carbohydrates in the same way.