The Principle of Homeostasis
Healthy Homeostasis
Your body tells you what it "needs." You know when you need to eat, or drink, and you have cravings for foods that supply the nutriments that you need.
Several studies have shown, that young children given a wide variety of foodstuffs to eat from, and freedom of choice, choose a diet that's surprisingly good, in terms of nutritional needs.
Homeostasis controls your body temperature, your weight, your blood sugars, the amount of cholesterol in your system, when you feel sleepy, your desire to exercise; - almost everything you do, is affected.
When your homeostatic system is itself "healthy" it will help you to be healthy too. But because of our personal behaviours, or because of social behaviours we adopt, we can force our homeostatic system to find another "set point" that is not so healthy.
Paleo Diet
The Paleo Diet does allow people to lose weight, but supporters have many strange ideas that are not science backed.
The idea that our bodies are adapted to eat seasonal foods, and the diet should include meat is valid. Not eating grains can also be supported as necessary for some people. Gluten intolerance and for some people an intolerance for wheat seem to be developed dietary problems.
The real reason Paleo works is that humans are adapted to cope with starvation. 
In history it's not normal for people to be well fed every day, all the year around. The body copes well with starvation, a point well supported by science. LCHF diets work for the same reason.
Control of Body Cells
All the cells in your body are under control. That control is from the signalling of other surrounding cells. Every cell requires "You're OK" signals from surrounding cells to continue to "live."
In the absence of "You're OK" signals; cells are programmed to switch themselves off. This process is called apoptosis. It's a process active in your body everyday.
Homeostasis is another example of this sort of control, with the signalling system being hormones and enzymes, linked into the nervous system as well. It's a whole body system; it can't be understood by looking at disassembled parts.
Your Body Adapts to Your Behaviour or Circumstances
Your body tries to find a way to cope with your behaviours, and makes the best adaptation between that behaviour, and the needs of your body.
We know that the body adapts to excessive alcohol use, drug abuse, over-eating, obsessive exercise, and to chronic pain.
The body also adapts to traumatic experiences, like child abuse, or repeated violence or warfare.
Prisoners kept in isolation, slaves, many women in abusive relationships, develop a delusional self-protective mental state, that makes them feel safe, yet reinforces their entrapment. That too becomes part of adaptive homeostasis.
We can call the new set point, that the body achieves, adaptive homeostasis. A place that "feels right," that allows you to continue with your life. This becomes how you normally are.
These forms of adaptive homeostasis are not healthy; they are just a way of coping. The long term effect of this sort of adaptation is likely to develop into a recognised physical or mental illness.
Dietary Homeostasis
Most of the time in our modern world people eat sweet foods or carbohydrates every 2-3 hours. This overloads the blood with glucose, creating a dangerous circumstance. The pancreas creates the hormone insulin, helping the body to use glucose as a primary fuel, and to store any excess glucose.
For most people this glucose based metabolism works well. However, you can force it out of balance.
The body learns to adapt to a constant excessive level of glucose, eventually becoming carbohydrate intolerant (alternatively named insulin resistant).
Throughout history, food supply has been erratic, seasonal, sometimes feast and sometimes famine. You see that now, in less developed countries or during war, when food supply is not reliable, people may be eating only one meal a day. Starvation introduces another form of metabolism, using ketones derived from body fat, and protein, or nutritional fat and nutritional protein.
The human body adapts perfectly well to metabolising ketones. Once you become ketone adapted your body will try to keep you in that homeostatic state. For instance if you do stimulate an insulin spike in your diet, insulin will be used to keep you in nutritional ketosis, rather than to switch back to glucose metabolism.
Atkins Diet
The New Atkins Diet, is supported by the same research that these pages talk about.
The focus of the New Atkins Diet is weight loss. The focus of Ketogenic Diets, and the Banting Diet, is to develop a lifestyle that supports you living in ketosis 95% of the time.
Ketogenic diets seem to have many unexpected health benefits, even beyond fixing the metabolic syndrome problem and protecting you from heart disease.
LCHF Diets
Stephen Phinney advises, "If you are completely happy with your body, health and performance on a high carbohydrate diet there is probably no reason to consider a low carbohydrate diet."
The Banting Diet, and other low-carbohydrate high-fat diets have objectives beyond simple weight loss.
Your body will function quite happily to use a ketone metabolism, rather than a glucose metabolism.
There seem to be a number of health benefits that flow on from a ketogenic lifestyle.
First, less muscle stress and faster recovery when doing heavy work or exercise. Low carbohydrate diets are anti-inflammatory.
You'll have the ability to go on for many hours without eating and not feel hungry.
LCHF diets are the preferred approach to correct metabolic syndrome.
Because LCHF diets restrict insulin supply, pre-cancers will have difficulty getting enough glucose to develop into a tumour. There's a better chance therefore, for you immune system to find such cells and eliminate them.
