I'm 95kg, 195cm tall. Aiming to lose some fat, eating < 50g carbs a day. I know I need fat to generate ketones for healthy brain function,

should I avoid eating fat so that my body uses my own stored bored fat to generate glucose or should I still eat fatty foods? (coconut oil, nuts, fat from steak etc...)

Thanks! (O.o)/")

  • How does your question relate to the context of this site? See the fitness.stackexchange.com/help/on-topic
    – FredrikD
    Dec 28, 2014 at 13:54
  • @FredrikD This is not my question, but I will answer yours; many experts assert that diet is the primary factor in a person's physical fitness. This is very clearly off-topic per the guidelines, but perhaps the correct action would be to migrate it to the health site which has guidelines listing, "Environmental or nutritional factors that affect health", as on-topic, rather than to just close it. Jul 8, 2018 at 5:21

3 Answers 3


I'm in favor of low carbohydrates for two primary reasons:

  1. Ketosis is legimate, effective, and safe way to cut down on body fat. There are examples of native people who historically ate very little carbohydrates for generations.

  2. Most of the sinister cheap calories in a western diet come from carbohydrates. Even following a "low carbohydrate diet" still has you ingesting more than you probably want to.

should I avoid eating fat so that my body uses my own stored bored fat to generate glucose or should I still eat fatty foods?

Keep eating fatty foods, and keep eating protein. I would also add in there there are a lot of vegetables that are low carbohydrates. Things like tomatoes and lettuce tend to be pretty low in the carbohydrate spectrum.

I'm of the opinion, backed by a lot of professionals, that carbohydrates are not necessary in your diet. This was a fairly balanced article on the whole issue:

Although there is certainly no evidence from which to conclude that extreme restriction of dietary carbohydrate is harmless, I was surprised to find that there is similarly little evidence to conclude that extreme restriction of carbohydrate is harmful. In fact, the consequential breakdown of fat as a result of carbohydrate restriction may be beneficial in the treatment of obesity. Perhaps it is time to carefully examine the issue of whether carbohydrate is an essential component of human nutrition.

One of my more preferred nutritional writers is Lyle McDonald, who takes it a step further and makes the distinction between glucose and glycogen which can often be (incorrectly) used interchangeably:

When carbohydrates are restricted completely, the body still has a small requirement for glucose (although this decreases over time) and the body has to find something to make glucose out of. That something is lactate and pyruvate (produced from glucose metabolism), glycerol (from fat metabolism) and some amino acids. It’s the amino acid use that can be problematic since they have to come from somewhere.

If you're aiming for <50g of carbohydrates a day, you need to keep your protein and fat up because your calories need to come from somewhere. Protein in particular matters a lot because your body will breakdown proteins (as well as fat) to produce glucose.

Also, take care to ensure you're getting enough nutrients. Those 50g of carbohydrates should be almost exclusively vegetables.


Although I disagree with taking on a low carb diet (with special medically advised exceptions), I'd advise you to absolutely consume fat, particularly healthy plant based fats, like nuts and avocados. Avoid animal based fats.

Fat will be your primary energy source if you're trying to induce ketosis.

But once again, there are far more effective ways of changing your body composition, and realistically speaking, are you willing to eat like that the rest of your life? Otherwise it's simply temporary, and why would you put yourself through the hassle?

  • Why do you disagree with a low carb diet? Yes I do alot of weight lifting daily for body composition changes etc.. Dec 26, 2014 at 2:36
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    Carbohydrates are your primary source of energy, and ketosis typically occurs during a period of severe caloric intake deficiency. It's needlessly stressful on the body and losing fat is going to be healthier if you just eat cleaner and become more active. Train the movement, not the muscle, and the muscle will come. No Olympic athlete is going on a low carb diet, it's just not conducive to your performance. Typing on my mobile, sorry if I'm coming off as vague. Dec 26, 2014 at 3:17
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    I'd much rather have you cut your calories and eat cleaner than remove or restrict what I consider to be a fuel source necessary to your future success. Dec 26, 2014 at 3:18
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    Carbs are only your primary energy source if you decide it to be, if you eat mostly fat, fat will be the primary energy source. If you eat a low carb diet with a normal amount of calories, ketosis will occur without starvation. I agree about athletes though, we will never a see many non-endurance sport athletes on a low carb diet. I think low carb diets can be a good way of losing weight if you tend to eat a lot of carbs and if you have low culinary and athletic ambitions :)
    – Mårten
    Jan 26, 2015 at 9:51

Assuming that you are able to generate ketones from your stored fat, it's still a bad idea to under-eat fat, because each fat cell can only deliver a certain amount of energy per day, when your calorie deficit goes beyond this point, you will start breaking down muscle tissue (which is much lower in energy density than fat tissue), leading to rapid but bad weight loss.

  • I'm not saying I have a reason to think you're wrong, but I would really like to see a reference or study that supports this max energy per day per fat cell claim. Would you be able to give me more information please? I find that very interesting. Jul 8, 2018 at 5:26

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