Why Biochemistry Makes It Hard to Lose Weight

In Fat Chance: Beating the Odds Against Sugar, Processed Food, Obesity, and Disease, Dr. Robert Lustig, MD addresses a global pandemic at the heart of a medical, social, and economic crisis: OBESITY. He begins by taking aim at the power players who’ve contributed to this unfortunate state of affairs:

  • The commercial food industry that serves up nutritionally deficient foods rich in sugar and fats (factors known to heighten appetite)
  • The medical profession who relegate treatment to personal choice and willpower
  • The insurance industry that offers no reimbursement for treatment
  • The obesity profiteers who make billions of dollars annually on weight loss supplements, programs, and specialty foods amid rising obesity rates

obesity pandemicDr. Lustig does not deem it rational to ascribe personal responsibility to the obese individual. That posture fails to take seriously the underlying biochemistry that perpetuates the condition. He argues that biochemistry drives behavior. Here are a few highlights from that discussion:

Our fat cells produce leptin when they’ve deemed that we have enough stored energy to attend to our needs and maintain our weight. It tells our brains that it’s OK to stop eating. Unfortunately, obese individuals develop leptin resistance. As such, the brain doesn’t get the message that its energy reserves are just fine. It worries about the threat of starvation and generates sensations of hunger. It also slows down the metabolism to ensure that it won’t overrun its reserves. It directs the pancreas release insulin to ramp up energy storage and weight gain. Excess insulin makes leptin resistance even worse.

Our brain cells are wired for reward to motivate behaviors that ensure survival. As such, we’re built to find food consumption pleasurable and preference taste over nutritional value. In ancient times, sweetness proved a reliable indicator that something was safe to eat. Sugary fruits came to full bloom during summer months when the population needed to fatten up in preparation for winter, when food stocks are in shorter supply.

Sugar causes the pleasure centers in our brains to “light up” in ways that mirror addictive drugs. It wasn’t a problem in the days of yore when sugary foods were relatively uncommon. Today’s food manufacturers have found ways to produce sugar in mass quantity cheaply. They are well-aware of the fact that we get addicted to food. In particular:

  • We binge eat.
  • We develop tolerance and require escalating amounts to achieve the same levels of satisfaction.
  • We crave the desired foods and become depressed and/or anxious when experiencing withdrawal.
  • We fail to contain our undesirable behaviors despite the negative consequences (e.g. medical complications, social stigma, expense, diminished job prospects).
  • Overeating interferences with our lives and favorable regard for ourselves.

Stress contributes to obesity. Many of us use “comfort foods” to ease the tensions we experience in life. Unfortunately, stress eating elevates insulin output (which increases fat deposits) and cortisol (which impedes sleep). Sleep deprivation increases ghrelin (the hunger hormone), reduces leptin (the satiety hormone), and activates the reward system. The net effect is increased body mass.

Excess cortisol (stress hormone) encourages the body to accumulate belly fat (a.k.a., visceral fat). These fat deposits are more active metabolically than fat deposits in our extremities. Visceral fat drives inflammation and causes insulin resistance. Insulin resistance is associated with a high incidence of cardiovascular disease, hypertension, diabetes, and other chronic disease.

Dr. Lustig’s prescription for healthy weight management includes:

  • Eliminate sugar. It’s a toxin that damages the liver, turns proteins brown (like rotten bananas), and promotes addiction.
  • Take in at least 25 grams of fiber daily. It slows digestion and absorption to a rate that ensures proper food metabolism. It speeds the passage of food and waste through the gut which accelerates the production of leptin (the satiety hormone). It decreases blood glucose and cholesterol. It promotes beneficial bacteria growth in the gut.
  • Eat whole, unprocessed foods. Dr. Lustig is a fan of the Mediterranean Diet which emphasizes legumes, fruits, vegetables, unrefined grains, dairy, eggs, fish, olive oil, and wine in moderation.
  • Eat a healthy breakfast. Delayed food consumption elevates ghrelin (the hunger hormone) all day long.
  • Stop nighttime bingeing.
  • Exercise consistently. It supports growth of fat burning mitochondria in the cells. It reduces stress and releases mood-elevating endorphins in the brain. It helps the liver burn energy more efficiently.

That being said, he acknowledges the difficulty of transforming one’s environment to drive different biochemical responses. Most lifestyle interventions work for 3-4 months before relapse. Therefore, we need support systems in our healthcare institutions and social infrastructure to help people on the road to success.