In my younger days, out of necessity, I used to service my own car. Car engines then were much simpler, and using a small strobe light, spanners and screwdrivers, it was possible to set the timing and fuel/air mixture quite easily. These adjustments were necessary to get the best performance from the engine. Too much fuel or too little air would result in poor fuel economy. Wrong timing of the sparks would result in backfiring or rough idling, pinging, knocking or difficulty starting.
Likewise, the human body requires fine-tuning of innumerable factors for optimal performance. This is described by the word “homeostasis”, defined by the NCI Dictionary of Cancer Terms as “the state of balance among all the body systems needed for the body to survive and function correctly.” Another concept used by engineers is “tolerance”. To achieve optimum function, concentrations of substances have to be finely balanced. Too much or too little can fail the system.
Blood sugar is necessary for energising almost all cells in the body. Too much for too long is called diabetes. Too little can result in confusion, unconsciousness and death. Both too little or too much potassium can result in fatigue, muscle cramps and irregular heart rhythms. Blood pressure is maintained within narrow tolerances. Too little results in dizziness and fainting, too much can result in a stroke or heart failure. Too little thyroid hormone results in weight gain, fatigue, lethargy and feeling cold. Too much results in excessive weight loss, sweating, irregular heartbeat and irritability. These are just a few examples of countless factors in our body that need to be carefully controlled for optimal health. Most are intricately designed to function automatically, but our behaviours influence others.
Last month, in our regular article, we covered the concept of the energy density of foods. Eating mostly natural whole foods is the best way to balance hunger and satiety.
Stomach cells produce ghrelin (the hunger hormone) when our blood sugars are low. But it can also be artificially stimulated during times of stress. Consuming foods/drinks with high levels of free fructose may increase ghrelin, whereas eating unrefined carbohydrate or protein foods may suppress ghrelin levels. Eating the typical Western diet with high levels of fructose (as in sugar) and refined carbohydrates may thus cause our appetite to be increased artificially.
Leptin is the satiety hormone produced by fat cells. The more fat in these cells, the higher the leptin blood levels. Children with the inability to produce leptin become profoundly obese, but if given leptin artificially, they rapidly lose weight. The majority of obese people have leptin insensitivity (similar to insulin resistance in type 2 diabetes). Laboratory research shows this is caused by inflammation of the hypothalamus in the brain, commonly induced by excess dietary saturated fat. The main sources are animal fats, and palm oil (found in almost all processed foods).
Dietary fibre encourages our intestinal micro-organisms to manufacture short-chain fatty acids (SCFAs). These stimulate the production of leptin, but also the short-term appetite suppressants PYY and GLP-1 by L cells that line our colon. These are potent appetite suppressants. (Expensive GLP-1 agonists are now given artificially for diabetes and obesity control).
Natural body mass homeostasis is best achieved by eating a diet rich in plant-derived fibre and low in saturated fats and highly processed carbohydrates.
