Why does Intermittent fasting work ? Sugar, Ghrelin and Obesity

Updated: Nov 9, 2020

What is wrong with the modern diet?

I actually stumbled on to fasting surreptitiously during an unplanned 48 hour fast.  I was surprised I didn’t need food for this length of time, so I started researching.

A few months later I found some random dude on reddit who posted an impressive weight loss from Intermittent fasting.  That was it for me, I ramped up my research and started IF.

I found that intermittent fasting is currently the most common diet and had huge health benefits. I wanted to know more and understand why. Hilariously, I thought, its completely free, actually it saves you money because you eat and thus spend less. It seems like the perfect diet.

Why is Intermittent Fasting effective?

There are many ways to understand why intermittent fasting is effective at losing weight and being healthy for you. 

From an evolutionary stand point, our ancestors did not have fridges enabling food to be on hand at all times.  We did not have food producers trying to sell and market food to us and we didn’t have 24 hour stores.  We also lived in small communities for survival, providing an educational and observational shield guiding our lifestyles.

Food was basically eaten as it was caught in the nomadic way of life.  There was no farming or animal husbandry, there was no genetic engineering to alter our food.  Our ancestors diets had less carbohydrates and sugars compared to our modern diet and they did not eat food as often as we do.   Are these two factors linked?

Our ancestors would hunt or gather for most of the day , returning to camp to eat before dark.  they did not have three meals a day and their digestive, and homornal feedback mechanisms evolved  on this model of food consumption over millions of years. [8]

The Homimin Evolutionary Timeline

The concept of time is often lost on us today. We think that we are the epitome of advanced human civilisation, yet, our narrow perspective forgets where we have come from and how we developed.  Our digestive and hormonal body systems evolved over millions of years. Yet, we have changed our diet dramatically over an extremely short period.  There is no way, our bodies can adapt to a diet change that fast.  


So lets fast forward to today.  We have relatively the same body systems but a completely different lifestyle. The modern cultivation and consumption of refined sugars took off in the 16th century.  The Atlantic island of Madeira, began commercial refinement of sugar which lead to the Portuguese establishing large scale production in Brazil to feed the ever growing desires for sugar in Europe. From this point, the world was hooked on sugar and we began  providing our bodies  with increasing amounts of this exotic sweet substance.

Madeira, began commercial refinement of sugar
Madeira, began commercial refinement of sugar in the 16th Century

Sugar is Extremely Energy Dense and ADDICTIVE.

Our bodies had evolved from an environment with very little refined sugars for millions of years.  We have increasingly flooded our diet with too much energy.  The change in diet was too fast and overwhelmed the system which had evolved over millions of years.  This overeating and overnutrition  is converted to fat, and that is why Modern Society has an Obesity problem.

For some reason we see the need to eat three meals a day and have high amounts of sugar in almost everything we eat. This overconsumption of high energy food has lead to Obesity.

The developed world’s largest rising health issue is OBESITY.  This has lead to a myriad of other obesity related health issues.

Obesity is killing us, WHO stats and statements [9]

Obesity is one of the leading risk factors for premature death. It was linked to 4.7 million deaths globally in 2017.

These numbers are insane.

Obesity is determined by the balance of energy intake and expenditure. Rates have increased as the calories have become more readily available. "The profound changes in the environment (eg, in diet and other lifestyle conditions) that began with the introduction of agriculture and animal husbandry ≈10000 y ago occurred too recently on an evolutionary time scale for the human genome to adjust. In conjunction with this discordance between our ancient, genetically determined biology and the nutritional, cultural, and activity patterns of contemporary Western populations, many of the so-called diseases of civilization have emerged."[8]

Amazingly, Obesity is preventable. Recall that we think our civilisation is advanced and think about these numbers again. A humble suggestion, but the Modern diet needs to change.

The Sugar and Ghrelin Cycle

So why does our body tell us to eat three times a day?

Sugar is in high proportions in the modern diet.  It's there because its cheap, its addictive and this can and is abused by Food producers.

A typical modern morning in the developed world, you wake up, and have breakfast. 

During the night you obviously were not eating and your blood sugar has dropped. The Hunger hormone GHRELIN, the  “sugar fixer”, is released by the stomach, commanding you to get food/ sugar, and breakfast is the solution.  We will address what is actually eaten for breakfast later, but of course it contains huge amounts of sugar.

Studies examining sugar ingestion and its effect on Ghrelin have shown that , Sugar will reduce Ghrelin levels.  That is, Sugar will reduce your Appetite and Hunger.   We have discussed this relationship in a previous post regarding how Sugar effects ghrelin and therefore hunger. The study showed ,The ingestion of all four sugar solutions resulted in.....ghrelin suppression.

After eating breakfast, Ghrelin reduces and so does your appetite. Leptins increase giving the feeling of satiety. A few hours later, your blood sugar drops and ghrelin hormone has again risen, insisting that you satisfy the sugar needs or CRAVINGS with another meal....lunch.

Ghrelin makes you hungry, you eat lunch all is good again.  

This process occurs again in the evening , ghrelin is released, you become increasingly hungry and you find your next meal, dinner.  

Despite having had far too much food for the day, we will often seek Dessert, as well as snacks throughout the day all containing of course......MORE SUGAR.

This system works efficiently like clockwork, except you are consuming too many calories.

Unfortunately your body's systems are not designed to cope with this modern lifestyle.  Your body responds to the constant blood sugar rises sending Insulin levels skyrocketing without control and you become Overweight. 

This leads to Obesity and type 2 Diabetes Mellitus, the fastest rising health concerns in the developed world.  

Honestly we cant keep living like this.  Our modern diets and lifestyle choices are killing us.

The Addictive Cycle with Ghrelin and Sugar can be retrained

Intermittent Fasting is the most popular diet in the world currently.   Intermittent fasting, breaks the cycle of sugar and ghrelin controlling your dietary intake of food.  Once you have reduced your food intake and mastered the “false” hunger pains, Ghrelin will not be secreted and the cycle will be reset.   

Instead of 3 hours between Ghrelin cycles, blood sugar rises and meals,  you can push this to 16 hours or more.  

Clearly, we don’t need all the food we are currently consuming and it is well within our capabilities to reverse this trend of overeating and the diseases it brings. Many people have adopted intermittent fasting into their lives. I can function at high exercise levels 20 hours into a fast. The concept of this is beyond many of us, because of the Food industry, reinforcing that you need sugar and to eat.

2 billion Muslim’s practice fasting on masse every year during Ramadan.  That is fasting every year for one month.  One quarter of the world's population, reducing their eating windows between  dusk and dawn, on average a 12 hour fast. Yet the modern world seems fixed on the idea that we need to constantly consume food and energy.

IF will break the Ghrelin / Sugar Cycle

IF will break the Ghrelin / Sugar Cycle that forces you to eat three unnecessary meals a day.

Your blood sugar level will stay low, \Insulin will not be secreted as much and your body's blood sugar/ insulin release gradient will be reset to a lower and much healthier level.  With less insulin secretion the cells of your body will adjust to lower levels of insulin, thereby reducing their insulin sensitivity. As a result, there will be less fat deposition and less predisposition to weight gain and Type 2 diabetes.

IF works to reset the Ghrelin/Sugar feedback loop. By fasting you cause Ghrelin to rise, however the hunger mechanism that it illicits can be moderated at the central level. As shown in previous posts, Water also reduces Ghrelin levels. Those that fast are able to control and moderate the effects of Ghrelin and thus reduce its impact.

We will continue this discussion regarding the modern diet, its impact on our bodies and on our society. We will also have upcoming posts going into more detail what IF can do for you. Subscribe to stay informed and updated for our next post.

1. Cummings etal, Ghrelin-leptin tango in body-weight regulation.2003, Gastroenterology 124:1532–1535
2. Asakawa A, 2001 Ghrelin is an appetitestimulatory signal from stomach with structural resemblance to motilin. Gastroenterology 120:337–345
3.Grajower, etal. Clinical Management of Intermittent Fasting in Patients with Diabetes Mellitus. Nutrients. 2019;11(4):873. Published 2019 Apr 18.
4. Williams, etal, 2003 Meal-related ghrelin suppression requires postgastric feedback. Endocrinology 144:2765–2767
5. Friedman JM 2002 The function of leptin in nutrition, weight, and physiology. Nutr Rev 60:S1–S14, S68–S87
6.Olszewski etal. Excessive Consumption of Sugar: an Insatiable Drive for Reward. Curr Nutr Rep. 2019 Jun;8(2):120-128.
7.Michael P. Richards, et al., Isotopic evidence for the diets of European Neanderthals and early modern humans, Proceedings of the N