Sounds good in theory (sugar is bad), but it sounds stressful (body starts producing ketones due to suck a lack of sugar, flu like symptoms for a week).
Potential consequences of reduced carb intake are weight loss. It can be used to treat type 2 diabetes, epilepsy, a wide range of neurological disorders, some cancers (yeah, really), and much more.
I'm not aware of any scientic data that found adverse consequences. You get a lot of resistace from health professionals because for the last decades what you eat on a ketogenic diet has been blamed for heart diseases or high cholesterol, but there never was scientific evidence to back up those claims.
Here is a a long term study that shows that low carbohydrate, high protein diets were correlated with higher mortality rates. It's an observational, not a controlled study, so the usual caveats apply, but it's definitely some evidence that there's no automatic win for low-carb, high protein diets: http://folk.ntnu.no/lyngbakk/artikler/trichopoulou.pdf
I'm pretty sure I've seen another study that linked long-term use of low-carb, high protein diets with increased incidence of cancer, but I can't find that study at the moment.
Edit: Let me also add that meat consumption seems to be mostly problematic with processed meat (http://www.ncbi.nlm.nih.gov/pubmed/23497300)
You can find an 'observational' study to promote nearly any point of view. If it's not a properly controlled peer reviewed study it's not worth anyone's time except the shills who got paid to write it up by whatever corporate group commissioned it.
One of the possibly side effects is decreased kidney function from the rapid increase of proteins in the diet (which don't metabolize very cleanly compared to fasts or carbohydrates). People with kidney issues or possible problems should avoid these diets. Kidney stones are much more common IIR.
Another is lower bowel problems as these diets frequently don't have enough fiber in them to keep things moving.
I lost a ton of weight (about 60 pounds) but I also had some weird problems that made me give it up:
- I felt unbelievably hungry all the time. Even after eating a huge meal. This is supposed to go away after a few weeks, but months into the diet I still felt like this.
- I felt like grease was oozing out of me at all times. I just felt icky and couldn't ever feel completely clean.
- My hair and fingernails grew at astonishing rates. I was cutting my nails every 3 or 4 days at one point.
- I had wretched B.O.
- I was constipated all the time. Low-carb fiber supplements solved this.
Good things:
- My mental clarity was unbelievable. You don't get drowsy in the middle of the day, and you don't really need anything to help wake up.
- I was doing lots of sports then and injuries healed so fast I felt like Wolverine. I never bruised during this time and I was doing full contact kickboxing.
- I was easily the strongest I've ever been.
- Weight loss was pretty constant till I hit a nice comfortable plateau at a good weight for me (a little under 160).
I've also done vegetarian diets and for a brief spell vegan diets. It's hard to compare how much better I felt overall on the first diet than the vegetable based ones though.
https://en.wikipedia.org/wiki/Ketogenic_diet
http://site.matthewsfriends.org/uploads/File/StonesPolycitra...
http://www.webmd.com/diet/high-protein-low-carbohydrate-diet...
"By restricting carbohydrates drastically to a mere fraction of that found in the typical American diet, the body goes into a different metabolic state called ketosis, whereby it burns its own fat for fuel. Normally the body burns carbohydrates for fuel -- this is the main source of fuel for your brain, heart ,and many other organs. A person in ketosis is getting energy from ketones, little carbon fragments that are the fuel created by the breakdown of fat stores. When the body is in ketosis, you tend to feel less hungry, and thus you're likely to eat less than you might otherwise. However, ketosis can also cause health problems, such as kidney failure (see below)."
"What Are the Risks Linked to High Protein, Low-Carb Diets?
High protein, low-carb diets can cause a number of health problems, including:
Kidney failure. Consuming too much protein puts a strain on the kidneys, which can make a person susceptible to kidney disease. High cholesterol . It is well known that high-protein diets (consisting of red meat, whole dairy products, and other high fat foods) are linked to high cholesterol. Studies have linked high cholesterol levels to an increased risk of developing heart disease, stroke, and cancer. Osteoporosis and kidney stones. High-protein diets have also been shown to cause people to excrete a large amount of calcium in their urine. Over a prolonged period of time, this can increase a person's risk of osteoporosis and kidney stones. A diet that increases protein at the expense of a very restrictive intake of plant carbohydrates may be bad for bones, but not necessarily a high-protein intake alone. Cancer. One of the reasons high-protein diets increase the risks of certain health problems is because of the avoidance of carbohydrate-containing foods and the vitamins, minerals, fiber, and antioxidants they contain. It is therefore important to obtain your protein from a diet rich in whole grains, fruits, and vegetables. Not only are your needs for protein being met, but you are also helping to reduce your risk of developing cancer. Unhealthy metabolic state (ketosis). Low-carb diets can cause your body to go into a dangerous metabolic state called ketosis since your body burns fat instead of glucose for energy. During ketosis, the body forms substances known as ketones, which can cause organs to fail and result in gout, kidney stones, or kidney failure. Ketones can also dull a person's appetite, cause nausea and bad breath. Ketosis can be prevented by eating at least 100 grams of carbohydrates a day."
There's tons more. But I can't be bothered right now.
I've gone on keto 3 times, for different periods of time, and after being off of them for a month or so, I've developed kidney stones.
I have no idea if they're related, but I am the only one in my family that gets them (no medical history) and it's the only 'abnormality' in my normal, generally healthy, life.
In practice, you cannot contract a dietary deficiency disease from eliminating sugar unless you have a genetic defect affecting liver function. Even if you also eat no protein, your body will self-cannibalize muscle tissue to keep the brain alive.
It appears as though the evolutionary pressures on humans have produced support for two different energy metabolisms. In times of feast, where sugars and starches are consumed in excess, the body operates on glucose and glycogen, and stores fat. In times of famine, the body operates on ketones produced from its own body fat, and the brain operates on a combination of lactic acid and sugars scavenged from the body's protein stores.
The potential consequence of this is that if you ever do start eating significant quantities of sugar, your body will chemically signal that famine is over, and prioritize the restoration of your body fat stores. In other words, you can never go off the diet if you want to maintain your weight, as your body will want to turn every last scrap of excess sugar into fat as fast as possible.
This seriously sucks, because the brain is hardwired to love sweeter foods--foods that surround us constantly. It's like Lou Wu from Niven's Ringworld resisting the urge to eat the magic sweet potato that turns Pak breeders into protectors. Your limbic center wants that doughnut, no matter what that prudish frontal lobe says. So low-carb dieters have to consistently maintain a high level of sheer willpower for their entire lives. That may not be physically stressful in the cortisol-producing sense, but it is stressful mentally.
You absolutely don't need to to eat any sugar at all. Simply put, glucose (a monosaccharide) is what normally power our cells. Glucose can be produced from hydrolyzing longer carbohydrates, or even from fat and proteins via gluconeogenesis.
Suggested reading:
http://en.wikipedia.org/wiki/Gluconeogenesis
If you look at history we've never had so much sugar in our diet at any point in human history, not to mention the fact that most sugar isn't actually sugar but things like HFCS which has a higher glycemic index.
The keto flu may sound bad, but it happens because your body isn't used to producing ketones since you've never been in ketosis before. I've been on and off keto for the last two years, and I don't get a keto flu since the first time I went into ketosis.
People assume that's a bad thing, but that's not a trivial assumption. Yes, it's not convenient - but e.g. fever - while indicative of a disease, is most of the time a good thing (unless it is life threatening, taking down the fever with Tylenol or Advil is likely to prolong the disease). Those flu- like symptoms might be a good, if uncomfortable, process.
I don't know myself - I'm just pointing out that it is not necessarily an indication that keto is bad for you.
