Everyone’s metabolism craves something different. Learn more about what your metabolism needs and how it changes as you age from Dr. Noel Maclaren, an award-winning endocrinologist and Sunita Singh Maclaren, a medical anthropology expert in the new book, Maximize Your Metabolism.

Read an excerpt from Maximize Your Metabolism below. 


Hunger: Signals That Fine-Tune the Appetite

  Brain—The hypothalamus stimulates hunger, as well as the feeling of satiety. It is important to allow time for the brain to register fullness after food intake. Satiety is induced by chewing food, so in our view, which is supported by scientific data, juiced foods bypass the signaling that indicates feelings of fullness, resulting in higher calorie intake.

  Gut—Following a healthy meal or snack, the digestive tract has multiple gatekeepers that set off alerts to signal fullness. Commercially prepared foods are designed to override and distort our body’s built-in hunger modifiers. We recommend complex natural foods, eaten at a leisurely pace that stimulate the gastrointestinal satiety hormones.

  Fat cells—As surely as a hammer finds a nail, an increase in body fat changes a person’s appetite signals. Leptin is a satiety hormone produced by adipocytes or fat cells when the stomach fills. Insulin dysregulation makes the brain less responsive to leptin, and it also affects another metabolic regulating hormone, adiponectin. This means that you can develop the habit of eating past the point of appropriate satiety.

Gut Reaction: The Power of the Microbiome

Antioxidant foods like raspberries and cabbage reduce the presence of food-derived cytokines—a family of proteins that is associated with inflammation, pain, and aging.

The digestive benefits of inulin, found in the chicory root coffee of New Orleans, have been recorded in early civilizations. It is mentioned in the Ebers Papyrus of ancient Egypt, and written texts of Greeks and Romans, including Aristophanes and Horatius, recount descriptions of chicory eaten roasted or raw. Today it is a popular salad ingredient in Belgium, France, and the Netherlands.

Fat Cells: Exquisitely Designed Hubs of Energy?

A key issue for physicians treating metabolic disorders is managing high triglyceride levels, which contribute to liver damage and hardening of the arteries, which in turn increases the risk for strokes and heart attacks. High triglyceride levels can be corrected with dietary modifications that reduce consumption of carbohydrates, not fat. To minimize risks for heart attacks and strokes, we also pay close attention to other lipid irregularities like low levels of protective high-density lipoproteins (HDL), or good cholesterol, that removes other lipids from your blood stream.

Although it is often vilified, cholesterol deserves our gratitude. It comprises a major part of the structure of the brain and retina in the eye. It endows all animal cell membranes with life-giving fluidity and permeability. This commonly dread-inducing member of the lipid family is essential for the creation of vitamin D, adrenal hormones, and sex steroid hormones. Fat cells trigger chemical reactions involved in growth, immune function, reproduction, and other aspects of basic metabolism. Above all, the circle of life, the core of our means of survival, is accomplished by storing and activating fats, our energy reserves.

Energy: Speed, Strength, Movement

Contrary to popular belief, people who carry excess body weight have a higher overall energy expenditure because it takes more energy to support a larger body mass. Significant weight loss over a short amount of time predisposes a person to rebound weight gain, especially because successful dieters tend to have permanently low resting energy expenditures. Prolonged exercise increases insulin sensitivity. Regular, repetitive fitness routines increase the presence of muscle cell glucose transporter (GLUT4), thereby bringing more oxygen and nutrients to the muscle tissue.

It’s never too late to start. Late-blooming athletes should be inspired to know that studies have shown that there was no difference in starting age between higher skilled and lesser skilled athletes. Additionally, physical fitness, but not the level of physical activity, was associated with improved cognitive function, specifically with those areas of brain function related to language ability, attention, and processing speed. Motor skill acquisition leads to procedural learning, which can be retained for long periods of time.

Enhancing Cognition: Thoughts, Moods, and Memory

With aging, the brain progressively loses its capacity to metabolize glucose, especially in those who are insulin resistant. There is a stronger association between poor glycemic control (seen with type 2 diabetes) and a loss of memory, poorer executive control, and processing speed in the brain.

Paul Ehrlich, a German bacteriologist and Nobel laureate, in 1908 discovered that water-soluble dye, when injected in the bloodstream, did not penetrate the brain. The blood-brain barrier tightly controls the movement of molecules, ions, and cells between the blood and the central nervous system. Recently, magnified brain imagining has shown that leaks in the blood-brain barrier associated with metabolic dysfunctions like diabetes and insulin resistance are prevalent in people with Alzheimer’s, depression, and bipolar disorder.

Countering Stress: Cultivating Mental Resilience

Cortisol, a steroid hormone, is essential for life, supporting as it does our cardiac and immune capabilities. The physiological stress response leads to the release of cortisol from the adrenal glands, which increases energy availability in the short term. Chronic stress interferes with insulin signaling at a cellular level. Importantly, it increases the level of glucose in the blood. Bioscience research has repeatedly confirmed a direct correlation between higher blood glucose and cortisol levels in accelerating the onset of diabetes.

Venturing far from the Anglo-Saxon world lie timeless treasures and stratagems in cognitive restructuring. For example, between 500 and 200 BCE, the Indian sage Patanjali presented the goal of yoga (chitta vritti nirodha) as “the easing of mental fluctuations.”

In 1925, the psychiatrist William Sadler referred to “Americanitis” (a term that he borrowed from the psychologist William James) as “a result of the tension, the incessant drive of American life, the excited strain of the American temperament.”

Sleep: Circadian Rhythm and Blues

The French astronomer and physicist Jean-Jacques d’Ortous de Mairan observed in 1729 that mimosa plants unfurl their leaves in sunlight and curl them up at night. Even when placed in a darkened space for several days, the plants continued to follow this diurnal pattern. He surmised that the plants were controlled by an internal mechanism now known as the circadian clock.

Habitual sleep deprivation leads to a classic three-dimensional portrait of insulin resistance: chronic fatigue and weight gain often accompanied by depression. Poor quality or short sleep (less than seven hours on average) leads to lower glycemic control. During REM sleep, vital hormones are released for bodily restoration while cognition is promoted through dreaming.

Irregular breathing patterns, or sleep apnea, are found in up to 77 percent of overweight men and about half as many women in the same category. In our experience, sleep apnea treated with respiratory aids can be reversed with appreciable weight loss.

Hormone Imbalances: A Few Cases of False Alarms

A prolonged volatility of insulin levels also suppresses the actions of the body’s hormone transporter proteins called serpins (serine protease inhibitors). As a result, isolated measurements of certain hormones do not reflect their actual functional levels. This commonly leads to incorrect lab readings of low thyroid hormones or low testosterone, as we will explain more fully in Chapter 12.

Serpins regulate stress, sexuality, energy, heart rate, and circulation. They are involved in a range of bodily processes, including the transmission of nerve impulses and transport of hormones.

Finally, we believe that our clinic patients’ impressive outcomes can be attributed to the simple dictum of the Renaissance philosopher Francis Bacon, namely scientia potentia est, or knowledge is power. When someone arrives for a medical appointment armed with a scrawl of questions and sheaves of pages printed off the internet, we warm to them. Their curiosity and enthusiasm for probing the hidden secrets of their physique will, in our experience, lead them to become formidable champions of their own well-being.

The MetaKura program is based on clinical proof that as you explore the essential knowledge of the elements of the Metabolic Matrix and fine-tune your insulin levels, your mental and physical well-being will grow by leaps and bounds. As you learn how the ten elements of the matrix work together, how they affect you, you can repeatedly redesign your own matrix, in a manner that is uniquely beneficial to you.

Excerpted from the book Maximize Your Metabolism: Lifelong Solutions to Lose Weight, Restore Energy, and Prevent Disease by Noel Maclaren, MD, Sunita Singh Maclaren. Copyright © 2021 by Sunita Singh Maclaren and Noel Maclaren. Reprinted with permission of Grand Central Publishing. All rights reserved.