The real modern era began after World War I, with the advent of telecommunications, antibiotics, mass media, industrialized production and transportation all started around this time period. Industrial food production also began and quickly famines in industrialized nations became a thing of the past. Hunger today is virtually unknown. Obesity and type 2 diabetes are a crisis draining health care systems. Don’t believe me just look back at high school pictures of kids in the 1940s.
Some people blame sugar, high fructose corn syrup, the lack of physical activity, the sedentarization of society. All of this plays a role but one thing no one talks about is temperature regulation.
Keep in mind that for most of human history, thermal regulation and periodic starvation were NORMAL. Imagine being anything from the 15th century prince of Prussia in winter all the way back to the first caveman to cross Nepal. You would have spent much of your winter fighting cold and huddled around fires. You would face entire days with little to no food.
We already know that intermittent fasting is great, helps us burn fat, maintain ketosis, etc.
Feel the BURN?
Cold is generally used as a recovery modality but regular cold exposure definitely burns calories. If you sit in “cold water” (20C was used here https://www.ncbi.nlm.nih.gov/pubmed/10751106/ ) you can increase caloric burn above your basal levels anywhere from 90-350%. Now, while I won’t suggest you spend hours sitting in ice water (just like you don’t spend hours in sauna), 30 min a few times a week with lead to a rather significant increase in caloric expenditure. If you double your caloric output (which is the low side of this range) for 2 hrs/week you can easily burn ~350 kcal/week extra. That’s an extra pound of fat every 10 weeks. Now before you roll your eyes, there are of course other benefits including brown adipose activation, increased peripheral circulation, etc.
In an ideal world were you’d be sitting in 10C water for 30 min a day while, for example, listening to a podcast or a book. You would burn off extra 130 kcal/day or 1 pound per month. I realize this doesn’t sound like much but keep in mind, every 10 lbs lost has huge health implications.
In conclusion by adding cold exposure, fasting and exercise together you will defeat excess fat and will quickly improve overall health.