Truth from science?
Science can never be a source of unchanging truth. In the course of my life scientific understanding of many things have changed. However, with the internet, 
everyone can learn what the best new science is, and where there is disputed science too. It's possible to use new knowledge to reduce the barriers to our better health. Many of the things we know and believe, and have acted on, are no longer scientifically valid. It's up to you to update your knowledge.
Old Nutritional Science: There was a research roadblock caused by the wide acceptance of the low-fat high-carbohydrate diet for 40+ years. When you are young, your body is carbohydrate tolerant, you can eat sugar and other carbohydrates with abandon and your body will cope with the excesses you subject it too. Once a paradigm is widely accepted, many commercial and academic programmes are developed based on that principle. Even if new science proves that the paradigm is wrong, vested interest in the old principle can delay change, often for 30 years or more.
Disputed Science: There is a long history of long and bitter battles in science to establish a better form of knowledge. We won't call it "scientific truth." In nutrition in the last 50 years there have been a growing list of outstanding professionals who have tried to stand against "the machine" and until now most of them have lost. But that can't continue. Denial of what we now know is making too many people sick, and in all developed countries it's imposing a crippling cost on the health budget. That will stop.
Saturated fats were supposed to make people fat and clog the arteries. That's untrue. In the absence of insulin, saturated fats become the main fuel for your body. Vegetable oils were supposed to reduce our cholesterol and make us more healthy. Some of the modern vegetable oils produced for that purpose are cancer causing, especially if used for cooking. We are supposed to eat a low-fat high-carbohydrate diet, "a little bit of everything," and we were told fruit, vegetables and healthy whole grains were the best foods. That idea too is currently being challenged.
After fifty years of striving for low cholesterol, we discover that higher LDL-cholesterol doesn't on it's own cause heart disease. We've become less certain that the cause of cardio vascular disease is understood. Higher HDL-Cholesterol is protective (certainly in older people), and LDL-Cholesterol itself is probably harmless. Very small high-density LDL particles may or may not be important.
However, “eating a little bit of everything in moderation” tends to get out of hand. We eat too many “healthy carbohydrates” and develop an intolerance for them. (Like a drug addiction.) Over the years we've produced too much insulin, created inflammation throughout our bodies, and become increasingly insulin resistant. Tell tale signs are increasing weight, high blood pressure, high fasting triglycerides, and low HDL cholesterol.
Given the size of that problem, in developed societies affecting about 75% of us, most traditional nutritional research is disappointing for me. The easy sources of funding, promote research that reinforces the status quo. You can see from the lack of progress in last 30 years, mainstream nutritional research is trapped by what now appears to be a faulty paradigm.
Banting Diet and Athletic Performance
For athletes, carbohydrate loading, suppresses fat oxidation for days, not just a few hours. Carbohydrates give you energy-dense glucose, and builds glycogen supply, but that's only 2000 kcal, and when that's burnt you are done. You “hit the wall.” Fat oxidation is disabled by your dietary practice.
The body stores about 40,000 kcal of fat fuel, and 2000 kcal of carbohydrate fuel.
Entering a long distance event, while in ketosis, gives you ready access to the 40,000 kcal of fat fuel, so your can run for hours, and glycogen is conserved so you are protected from “hitting the wall.”
Ketogenic Diets - Research
Since 2002, there has been another thread in dietary research, looking at Low-Carbohydrate High-Fat diets. The studies are small, and tightly controlled, and the results are very interesting.
Stephen Phinney published about a low-carbohydrate diet in 1983. Gerald Reaven wrote about poor diet causing metabolic syndrome in 1997. Jeff Volek followed in 2002 with LCHF diets for athletes, and Hussein M Dashti began to publish in 2003. Since then there has been a flood of new LCHF dietary research.
Metabolic syndrome is a lifestyle disease, and most of us have it because we all live in a similar way. "Living normally" is killing us. With a little knowledge we can stop that. It's easy to fix, but you need to know how.
There is now good new science to support weight-loss. This science is not really so very hard to understand. It's about how dietary carbohydrate, controls the amount of insulin you are producing. If you exercise control over that, you'll easily be able to burn fat off your body.
Your weight depends on what you eat, and how your hormones respond to that. You control those hormones by choosing what to eat, and by choosing when to eat. The first thing to understand is that the overnight fast need not stop at breakfast time. By choosing what to eat at breakfast, you can keep your lipid metabolism running, until lunch, maybe until dinner time.
Nutritional Ketosis: It takes four days, but perhaps as long as fifteen days, to transition from a glucose burning metabolism to a ketone burning metabolism (Lipid Metabolism).
Health Benefits of Ketosis
There's more: for many brain related problems, fueling your brain with ketones has a metabolic advantage. And most cancers use glucose to fuel their rapid growth. Cancers generally can't thrive in a ketogenic environment. That's not a cure, but it opens the way for better treatment options.
Early stage cancers, pre-cancers, are very vulnerable to the hostile environment of your body, and your own immune system. In recent times, we've discovered that simple dietary methods can make it even more difficult for cancers to develop and become tumours. That's a good anti-cancer strategy anyone can use with little cost.
