Sorry about the rambling, I'm kinda sleepy today... and I'm so very sick and tired that people nowadays don't know how to eat and are scared of food (note, I myself fell into this trap and became unhealthy after I moved to USA)

By restricting calories, you are also restricting intake of nutrients. Not good!!
Anorexics aren't simply unhealthy because they restrict calories, they also have many nutrient deficiencies. This is not something you should sacrifice to lose weight.

I'm sure some people would consider losing weight on Paleo via heavy calorie restriction, for example, if they are facing a bad financial situation, then I guess they could have an excuse to get by with less food. But why someone would do this for more than a week is beyond me. (Yes, I read the low-calorie wiki thing you linked to)
I can see myself doing that if I had one week to fit into a.. umm.. wedding dress or some such; but I wouldn't do it more than one week.

A lot of people found Paleo after doing lots of low calorie dieting which obviously didn't work for them. It's not sustainable, after you stop the low calorie diet, you regain the weight. Plus other people have to deal with a grumpy you. Grr!!

You seem to have the impression that fat is unhealthy. It's not. Fat is very good for you.
There's plenty of information on fat on MarksDailyApple, Weston A. Price Foundation, and other places. Go to your library and ask for help finding very old fashioned cookbooks from cultures outside the USA. I stress they must be very old books, because now most of the world subscribes to the USA low-fat dogma.

Or read Nourishing Traditions book, it has old fashioned recipes, and explains about nutrients and fat, etc.

I was fortunate to grow up in a tiny island in the middle of nowhere. I'm only 24 years old but I grew up in a place where most people did not own TVs and did not own cars at all. I grew up eating home made meals the old fashioned way. We raised and butchered our own animals, made our own sausages, grew our own vegetables and fruits, and so did every family in that place. Our meals were naturally high fat, simply because that's how things are!

I mean, my mom cooked meat and vegetables, with plenty of animal fats, I mean, what was she supposed to do, travel to the future to get non-stick spray? Or throw chicken thighs and pig belly in the trash because they're "too high fat"? NO WAY! We ate what we killed or got from the garden, no more no less.

I grew up knowing that fat was very good for our health, everyone always talked about how it was so important.
Ask any grandma from old-fashioned times, she will tell you that to lose weight you should eat less bread, less potatoes, less rice, not fat!

I feel very sorry that you didn't grow up naturally like I did, if you did you wouldn't be so scared of fat.

I'm not saying that is what you should do, but maybe it helps you understand "fat ratios" since I come from a culture who knew how to feed themselves (unlike most people today):
I eat now the way I ate when I was growing up on that little remote island, and when I track stuff on fitday it comes to about 65% fat, mostly from meat and fish, lard and tallow, marrow, and eggs.
I don't do anything fancy, just heat some fat in a pan, throw in my piece of meat, throw in some vegetables. I don't understand what's so unhealthy about this :-)

Exactly! That low carb thing is so 1997 and yeah we all know all that fat just cannot be good for you. I mean come on people! Don't you read People Magazine!? And calorie restriction well that's for wusses. What all the fat people need to do is this but they're all too stupid and lazy and gluttonous that they probably can't push themselves away from the dinner table to get it installed. Stupid fatties. Losing weight is not that hard. They just need to stop eating so damn much! Honestly I don't think they even try.

I started Paleo as a 35 year old woman at 5'4" weighing 167 pounds with 28% bodyfat almost one year ago. I currently weigh 160 pounds and just got my bodyfat retested. I am now at 16%!! I did this eating very high fat Paleo, never restricting my calories. My resting metabolic rate is 1821 calories. So the concept that anyone can do ANYTHING healthy for their bodies at 800 cal/day is beyond ridiculous!

This is an untrue assumption

So, why risk the health damages of doing high fat paleo

Ain't nothing wrong with fat. Just don't get caught up in the pissing contests where people brag about how much fat they eat; that's not healthy either.

I spent 8 years (2000-2008) trying to lose a middle age gut, following all the 'right advice': low fat, lots of jogging, even a marathon in 2004.

I gave up for 6 months, got heavier, ran more, got heavier.....April 2008 I started a 25 year old, medically researched, commercial ketogenic low fat VLCD, 610-800 kcal/day. I lost 50 pounds in 4 months, wasn't hungry after the 3rd day. (no exercise for 4 months)

Then back to low fat, calorie counting, jogging. Weight started coming on again. Went online, Started reading.......

Taubes, Sisson, Briffa, Eades, Wolf, Leangains, Lean Saloon, PHD, Kresser. Guyenet, Harris, Masterjohn, FTA. LLVLC and many more. (Despite being a lapsed 1974 biology post grad I'd heard nothing of epigenetics. I got very excited about that in feb 2009) I forgot the low fat mantra (took a year not to feel guilty from the CW brainwashing) Did quite a lot of Dolson (low carb) to help break away from bread/cake/pasta shaped food.

Lost the belly again, lifted a little bit, ran a little bit, cold showers for 2 year. Settled into paleo+butter/hwc, for 3 years so far. Feel good!

Point of all this rambling is that it was the commercial ketogenic VLCD that finally introduced me to the fact that i could quickly, simply and easily influence my body to 'burn fat' by how i ate, and I am very grateful for that.

I'm 60. 5ft 8in. I weigh 155lb. (My father and brother, both 5ft 8in, died age 63 and 71. both 240lb+)

Because you got a lot of backlash on this question, I thought I'd put together a comment just explaining why it put me off right at the start. I flinch hard with questions like this, I didn't mean that link as aimed personally at you, but at the whole concept of "overweight people, why aren't you just eating less". I think it resonates emotionally with a lot of people here, which is why you're going to get some defensive backlash when discussing anything like this. Comes with the territory. Also, when you are discussing caloric restriction as a weight loss method, comparing it favorably to anorexia is pretty offensive for anyone that has experienced or been around someone experiencing anorexia. Saying that it is not anorexia just because the person isn't small enough puts a standard that you can't have a serious eating disorder until you reach "X" amount, which as many people will attest to, is not the case. You can be severely eating disordered and weigh any amount, healthy or unhealthy. Encouraging extreme caloric restriction and methods that encourage weight loss at essentially "any cost" (including satiation and happiness) is an encouragement of disordered eating a lifelong stressful relationship with food. I already put the stat up, but if you had a kid today that child would be 229 times more likely to develop an eating disorder than type two diabetes during childhood years. Yo-yo dieting, binging, anorexia, bulimia and many more can be the result of this behavior, all of which will cause enormous strain on your body. Even if you are just restricting calories and have all the psychosocial aspects under control, the saying is "the easiest way to gain 25 lbs is to lose 20" because most quick weight loss will be gained back plus some change.

Most people here didn't try paleo/primal/ancestral eating as their first kick at the weight loss can- I would challenge you to find one person who has lost a significant amount of weight that DIDN'T try some sort of low-fat caloric restricted diet. And yet, we are still all here, some people with some pretty amazing stories of improved healthy, well being, and, yes, weight.

It takes some experience to have a conversation like this. I'm younger than you, but I've walked the stepping stones enough to find out what is and is not appropriate to say (for the most part). It's good that you are working that out now, I mean you aren't going to learn if you don't try it! But I wouldn't be surprised if you get some negative responses when talking about weight loss if you haven't been around the conversation for very long. The most important thing is to listen in your position, to the other people in this conversation,.

800 calories is well below the basal metabolic rate for even the smallest people. I've never seen a recommendation below 1200 calories, and that's pushing the bottom limit. Personally, I attempted low-calorie, low-fat, and low-carb all at the same time (based on flawed CW and absolutely no research/prior knowledge), ate 1800 calories a day, and felt terrible. I dropped about 20-25lb, but I felt tired walking up too many flights of stairs, and I looked no better than I do now (probably worse, actually), consuming 3500-4000 calories.

You might induce ketosis by restricting calories, but you're also causing your body to break down muscle tissue, preserve fat tissue, slow your metabolism, and basically revolt against you, physically and emotionally. The weight loss benefits of ketosis are IMHO cancelled completely by the negative effects of extreme calorie restriction.

I think you are failing to realize that the "high fat" content of the paleo diet is coming primarily from mono-unsaturated fats from nuts, avacados, lean fish and meat. This should not be a detriment to ones health, nut rather an improvement. I technically have not lost weight on my 2 month paleo lifestyle adjustment, but my body has flourished. My stomach, hips, thighs, butt and all other fat storing regions have reduced in size dramatically. In regards to exercise, I have more endurance, stamina, and lung capacity than ever before, and I never feel hungry. The thought of eating a typical carb filled diet seems agonizing to me, and the taste of cheese, bread, and pasta generally repulses me at this point. Also, if you were to calorie restrict to the point of ketosis you would additionally deprive yourself of important vitamins and minerals, which a paleo diet amply provides. Yes, why the fear of fat? I suppose if your idea of paleo is eating nothing but fatty hamburger covered in bacon, you could be scared, however if that is the case, you have not researched paleo to any point of understanding, and have no grounds to judge it.

"Normal" healthy people who undergo caloric restriction show symptoms of disordered eating and mental illness post starvation. You can start perfectly fine, but imposed with severe calorie restriction, psychological and physical consequences can occur. With a high-fat diet, you can still go into ketosis without subjecting your body to that kind of physical and psychological torment.

There is a well-known study conducted around WWII in the 40s to stimulate severe famine. Subjects (all men) in the starvation group lost about a quarter of their body weight in a about half a year through induced starvation. It offers light on how eating disorders can develop from simple dieting or severe restriction. Calorie restriction can have pretty significant consequences. You might lose weight, but be prepared to lose your mind...

During the starvation period, the men experienced severe depression, decreased sex drive, social withdrawal, preoccupation with food and body dissatisfaction. Keep in mind, these men were healthy before being subjected to starvation. If you think you are tough enough to avoid the psychological consequences, there were physical consequences as well. Metabolism (BMR) dropped and body temperature dropped.

Also, during this starvation period, the men became obsessed with food..collecting recipes from magazines, one stole food from the garbage and another ended up having to drop out because he had to be in a psych ward. In the next phase of the study, during rehabilitation, many started to binge-eat. This is very common people who may start their eating disorder with typical anorexic behaviors. The mind is a powerful thing, and the body can sometimes be overridden...and then the out of control binging begins. And by binging, some people REALLY binge, as in 10,000 in one sitting because your body doesn't know when you will try to restrict again. The men eventually "normalized" their eating but it took like half a year.

So... You are suggesting an overall calorie deprivation to attain weightloss instead of an adequate-calorie approach?

And this is better why?

Many of us did calorie restriction and failed. The physical stressors of starving yourself isn't ultimately successful, aggrivates eating disorders, and is less-effective, in many cases.

Your only qualm is he oft-unproven concepts that eating adequate, and surplus calories from fat, are in fact detrimental.

What makes you think starvation-induced ketosis is healthier, short or long term, than high fat (define high) paleo?

EDIT: why even bother with ketosis, not necessary to lose weight?

I think the difference comes from the peace of mind that you get with actually being satiated. 800 calories a day and likely you will spend hours on end thinking about the food you are NOT eating.

A high fat/high protein diet will leave you feeling satisfied and allow you to be free to carry on your daily activities without obsessing over your hunger.

Well, I've done low calorie diets in the past and it wasn't healthy because I was still eating processed foods. I started paleo in October. I weighed 210, and now I'm down to 164 and still losing weight. I have so much energy and my body just feels healthy. I don't get food cravings anymore. I'm losing fat where I had issues losing fat on a calorie restricted diet. I'm not doing paleo to just lose weight. This is a lifestyle change for me and my family. No more processed foods, sugar, dyes, etc.. I don't do as high of fats as some do. I don't use butter. Just not a big fan of it. I have some large family members that do calorie restrictivediets, and it gets them nowhere. They will lose weight and then gain it right back.

You asked "why risk the health damages of doing high fat paleo"

I could easily turn that around and ask "why risk the health damages of calorie restriction".

Overweight individuals could severely cut calories and lose weight, I'm sure. However, many may find that their metabolism and energy levels decrease as a compensatory adaptation to this diet. This is certainly counterproductive to their goals, and may be in addition to other health risks associated with a low calorie diet, like increased bone and muscle loss.

A high fat diet may allow people to eat ad libitum, while still eating less calories than they burn, resulting in weight loss. This seems like a better weight loss strategy to me. Or, don't eat high fat (I agree with you in saying "I also think that insisting on doing high fat is why so many fail to reach their body composition goals"). I have lost weight easily eating as much potatoes, bananas, and rice as I want. But forcing yourself to eat less is not, in my opinion, the best strategy for weight loss.

This is wrong by the way. The only way you can get into ketosis is by carbohydrate restriction (or total starvation). The process is governed only by your carbohydrate intake (and to a certain extent your protein intake), the number of fat calories is incidental.

On a regular diet your brain burns about 100g of glucose a day. If you eat much less than 100g of carbs then it uses ketones as an alternative energy source (ketones are a bi-product of the breakdown of fatty acids). If you ate zero carbs, your brain would get 75% of its energy from ketones, and the other 25g from glucose generated from gluconeogenesis (from breaking down protein and a little fat).

If you get into ketosis on a 800kcal diet, its only because you've restricted your carbohydrate intake significantly below 100g.

If you 800kcal diet consisted of 200g of pure glucose, you wouldn't get anywhere near ketosis.

In order to get to the next level, you have to understand that saturated fat (and cholesterol) are straight up good for you. Butter is a health food.

800 calories a day is a recipe for disaster. Most can't actually discipline themselves that well, and those that managed to would suffer terrible nutrient deficiencies. I lost plenty with a 1500 cal restriction- with about 70% of that coming from fat.

Starvation!???? Any person with an abundance of fat stores has a looooong way to go until they are "Starving". That pathetic wimper of hunger 3-4 hrs after eating is more thirst mixed with psychological triggers than it is hunger, that HUNGRY! feeling after 3 DAYS without food is real hunger and as far as starvation goes? 99.9% of people in America have no clue.

To put it another way, unless your <5%BF, its IMPOSSIBLE to 'starve'.

I have been keto adapted for 4 months now. Fasting for 18-24 hours is nothing. Calorie restriction is no problem either. Once your body looks for fat as fuel it finds plenty stored all over your body and its not starving. If its burning is fat its happy. Just make sure your not kicking it out of "FAT" mode with a plate of carbs. Your body isnt starving if its burning fat, it usually has plenty stored all over. Its starving if fat is too low and your using your muscle for energy. Make sure you eat proteins and fats. Your liver will convert some the proteins into usable "sugars-glycogen" to feed the organs that need glycogen. So make sure you have enough protein for maintenance and conversion for those organs that need it. As far as energy though even being keto adapted your not going to get much energy in long intense exercise.

You're also missing that fat is more "filling" per calorie than carbohydrates are. You can actually eat fewer calories and still feel full by restricting your carbohydrate intake and increasing fats. It's one of the ways that standard nutritionists tried to explain away the Atkins diet as being a calorie restriction diet in disguise.

Tim Ferris talks a little about it... http://www.fourhourworkweek.com/blog/2008/02/25/the-science-of-fat-loss-why-a-calorie-isnt-always-a-calorie/

I imagine a lot of folks who have turned to VLC paleo were significantly overweight or obese. That is very different from someone at a healthy weight trying to improve body composition (i.e., for aesthetic or athletic reasons).

For someone overweight or obese, they can likely lose fat without the need for glycogen stores to get peak performance during workouts and often without even having to worry too much about calorie restriction (e.g., just by eating real food to satiety). This may also be easier as it doesn't require counting calories, counting macros, super high intensity workouts, etc.

For someone at a relatively healthy weight, trying to lean out, the above approach may not work (hence the plateau). In those cases, I imagine workout intensity matters a lot more, thinking more about calories may become necessary (especially if pushing below a theoretical healthy body fat % or setpoint or whatever). In that situation, adding in carbs and removing fat, may be necessary. You also might have to take it further and think about macro ratios and/or carb cycling/etc.