Ever since my early childhood our family has planned to spend at least one week per year in a game reserve. Life can get hectic; relationships can become humdrum; perspectives on life distorted. It is good to re-boot our emotional computers and reconnect with nature. We are fortunate in Africa to have a wealth of nature and game reserves, where we can experience natural Africa in all its diversity and raw beauty.
Over the years I have been struck with the observation that all wild animals, except in times of drought and famine, maintain a healthy weight. Some animals, like rhinos, elephants and hippos, are naturally large for good adaptive reasons.
However, I have never seen an obese giraffe or kudu or impala. Lions and leopards may look sleek and well-fed, but never obese. Hyenas and wild dogs maintain a healthy body weight in their natural state. But this ability to maintain a healthy weight is not shared by many domesticated dogs and cats.
Why is this? It boils down to whether the animals are eating and behaving in ways for which they were designed. Impalas, zebras and rhinos eat grass. Kudus and giraffe eat leaves from trees. Lions, leopards, hyenas and wild dogs are carnivores. Only three of 1,3 million animal species on this planet regularly have obesity issues – dogs, cats and humans. They are eating highly processed human or pet food. (Hopefully the humans are not eating pet food!)
Professor Barbara Rolls, a nutrition scientist at Pen State University, came up with the concept of energy-density of food. Highly processed foods such as chips, breakfast cereals, white bread, confectionary, sugar-sweetened beverages and oil, weight for weight, compared to whole foods contain dramatically higher levels of kilojoules.
Many studies have shown we tend to eat the same weight and volume of foods at each meal. But if we eat highly processed and concentrated foods, we will ingest much larger amounts of kilojoules.
By contrast, if we are eating natural whole foods (as our wild animal friends do), the normal homeostatic mechanisms (we will learn more about that next month) are better able to help us maintain a healthy weight. Very often energy-dense (highly processed) foods are low in nutritional density.
The least energy dense foods, yet highly nutritious foods, are salads and vegetables (50-150?kj per 100 g). Most fruit has around 200 kj/100 g. Boiled potatoes, beans and whole grains have around 300-500 kj/100 g. Contrast this with meat at around 600-1 000 kj/100 g, white bread and cheese, and pizza at 1 000 kj/100 g, chips at 2 000 kj/100 g, chocolate at 2 200 kj/100 g, and butter and olive oil at 3 300 kj/100 g. Plant foods in their natural state are high in water and fibre (no kilojoules) which increase satiety.
We can learn from our wild animal friends that eating the natural foods for which we were designed is the best way of maintaining a healthy weight.
- This health column is written by Dr Dave Glass, a retired obstetrician/gynaecologist living in Somerset West. He is also chairperson of the South African Lifestyle Medicine Association (Salma). With an MBChB, FCOG(SA) and DipIBLM, Glass has a passion for preventing and addressing the root causes of chronic diseases such as diabetes, heart disease, auto-immune diseases, obesity, dementia and cancer.
