In our previous article we referred to the calorie restriction diet as a blunt instrument for promoting longevity (see “Does Calorie Restriction Increase Longevity?“). This article will reveal the simplest and most effective strategy to extend lifespan without going hungry.

Ischemic heart disease, otherwise known as coronary artery disease, takes more lives every year than any other age-related illness. It seems a no-brainer that most nutritionists and medical practitioners recommend diets that minimize fats.

However, this is a simplistic view that has been challenged by recent discoveries in nutrition science. The sequence of events that precede heart disease are pointing to a different culprit, and that is sugar.

The role of insulin

Too much glucose in the blood is toxic and high sugar levels in non-diabetic humans signal the beta cells in the pancreas to secrete a hormone known as insulin.

Insulin proteins bind to receptors on membranes of fat, liver and muscle cells and promote the absorption and conversion of glucose into glycogen and fats. Glycogen stores are prioritized and they are mainly found in muscle and liver cells to provide highly available energy. Fat cells act as a buffer stock that absorb any excess glucose after being converted into fats known as triglycerides.

Individuals with higher muscle mass can tolerate more sugar intake without “getting fat” because the muscle tissue can hold a lot more energy stores in the form of glycogen. This higher muscle mass group is also more likely to be more physically active, which means that glycogen stores and glucose in the blood are constantly being metabolized.

Side effects of insulin

In the presence of insulin fat cells also absorb triglycerides, which means that fatty acids that would normally be metabolized are also getting absorbed along with the excess glucose into fat cells. The effect on energy levels is noticeable after the initial surge in insulin, and it is commonly referred to as the insulin dump.

You become aware of this insulin dump one to three hours after eating a high-sugar meal. A non-diabetic body’s reaction is to mop up the glucose toxicity by releasing insulin in sufficient quantities to bring blood sugar levels within the normal range. This insulin release overshoots, and you experience a lower-than-normal energy level after your initial sugar high.

What this means is that a high sugar diet, especially when coupled with fats, creates an energy surplus that exhibits itself in weight gain over time. This is made worse in the presence of fats because insulin also signals fat cells mop and store these fatty acids as well, even when the signalling mechanism began with elevated glucose.

Insulin also signals our kidneys to reabsorb sodium. This is corrected when insulin levels drop, but in cases where there are chronically elevated levels of insulin, it can lead to high blood pressure.

Insulin resistance and the other metabolic disease

As we age, our cells develop a resistance for the insulin signaling mechanism. As more and more insulin is utilized over a lifetime, insulin resistance develops in cells, and blood sugar levels stay elevated for longer. The pancreas reacts by secreting ever more quantities of insulin that inflict damage throughout the body.

In extreme cases, some develop an intolerance to sugar and carbohydrates, a disease otherwise known as type 2 diabetes. Even as it ranked the 6th cause of death globally in 2015, it also creates a whole set of problems that accelerate the aging process.

Diabetics are more likely to have high blood pressure and high cholesterol, and they are more likely to die of a heart attack or a stroke than non-diabetics.

They are more likely to have peripheral arterial disease, nephropathy, retinopathy, and possibly neuropathy and cardiomyopathy. In fact, more than half of diabetic patients die of ischemic heart disease.

Elevated levels of insulin also impair uric acid secretion. High levels of uric acid in the blood cause gout, which is not surprising given that it seems to affect people with diabetes.

Inflammatory response

When insulin works to expand fat cells, one result is an inflammatory response in the form of molecules called cytokines. Basically, fat tissue grows to the point where fat cells begin to die. Cytokines are called into action to clean up, but this is not a normal response to some pathogen, and the inflammation can become disruptive to the body’s normal functions.

The inflammation has nothing to do with fighting off germs, and when it becomes chronic it can potentially result in a long list of disorders: arthritis, asthma, atherosclerosis, blindness, cancer, diabetes, autism and mental illness.

Oxidative stress

High sugar levels in the blood is also linked to oxidative stress. Oxidation refers to the process of creating “free radicals” that cause damage to tissues they interact with. When oxygen is metabolized, molecules without electrons are byproducts that react with tissue such as artery walls, and cause damage by stealing electrons.

Free radicals can react with lipids, proteins, and DNA. They are associated with a number of diseases – for example, neurodegenerative diseases like Alzheimer’s and Parkinson’s because damaged proteins kill brain cells.

Elevated levels of insulin and sugar also create dangerously high glycation levels, which creates harmful molecules called advanced glycation end products (or AGEs). AGEs damage tissues throughout the body, including walls of arteries and tiny capillaries. When this happens, inflammation leads to the accumulation of fat and plaques in the artery walls, a disease known as atherosclerosis. This increases the risk of heart attacks, strokes, and other vascular disease.

Glycation is also linked to poor mitochondrial function, and it accelerates the aging process. It also triggers aging in skin cells and the premature aging in diabetics.

Link to cancer

Recent research also links dietary sugar with cancer. This is not surprising considering the increase in the rate of free radicals inflicting damage to DNA.

To conclude

Unless you have a medical condition that requires you to supplement with sugar – for example hypoglycemia – there is no good reason to add simple sugars to your diet. Even athletes do a lot of damage to their bodies by consuming high-energy products containing large doses of sugar.

Yes, calorie restriction and longevity are positively correlated, but the trade-off between enjoying the pleasures of food and longevity makes it impractical for most people to follow as a lifestyle choice. Minimizing simple sugars permanently in your diet is a high impact change that you can reasonably adapt to. The addiction and craving for sugar will eventually fade.

It is also important to note that diseases brought on by sugar reduce the quality of life significantly long before death. It is something to think about when offsetting the “living well” vs. the “living long” trade-off. Sugar may give you short-term pleasure, but it comes at a high cost in overall well-being.