I find Low Carb Diets just fascinating. To me it is remarkable that they are as popular as they are. I eat what I would call a high protein, medium carb, low fat diet and love it. I love fruit in particular, beer, dark chocolate, quinoa and a lot of things that have carbs. I simply cannot imagine going with vegetables only. However, I recognize that Low Carb Diets are very popular with men, especially those losing weight. Low Carb Diets may even have some interesting applications, such as controlling certain types of cancer. 
That said, I have had concerns that some men - I'm not saying all - could hurt themselves with these types of diet. And I have raised up some of the negative studywork in my links on Low Carb Diets and Inflammation and The Potential Dangers of Low Carb Diets. And, anecdotally, some men seem do seem to be getting hurt from these types of dietary regimens. Below is a horror story from the Peak Testosterone Forum members as to how a Low Carb Diet made him just plain sick. So, if you're on a Low Fat Diet, and feel good, then no attack is intended.
But some of you could very well be experiencing some of the negative consequences of Low Carb Diets as this man did, including insulin resistance, inflammation and high cholesterol:
GUEST AUTHOR: DdR
Q. You mentioned that you got down to 10% bodyfat on a Low Carb Diet. That' s quite impressive, of course, and so can you explain how you did that? In particular, can you give an overview of your diet?
A. Well, I say 10%, but it could've been 12%. I definitely had a six-pack. I lost three inches off my waist and could've worn size 30 pants no problem. I'm 5'11", 35 years old, athletic build.
I achieved this by using a combination of the programs from Bulletproof Exec, Lean Gains, and Carb-Backloading. In essence I would wake up and drink a cup of Bulletproof Coffee with 10 grams of whey protein mixed in (prevents catabolism of the muscle). That would keep me satiated until 2 p.m., when I would have my first meal, which would consist of animal protein (let's say tuna fish with mayonaise) and a vegetable (let's say steamed broccoli with sauteed garlic). I would eschew all carbs. My second meal would echo the first meal, i.e., protein and vegetables, little carbs. I would eat nuts too and allow myself red wine.
On workout days (workout = heavy weightlifting) I would follow the same program, but after hitting the gym in the afternoon, I would slam carbs together with protein until bedtime. It didn't really matter the amount of carbs, because I could only eat so much before getting sick. The theory is that carbs are being channelled towards the muscle cells to restore glycogen stores in lieu of going to fat cells.
My sleep would be atrocious that night after carb backloading.
At any event, I put on muscle while simultaneously losing weight. It was stupidly simple to maintain that body-fat percentage as long as I got used to it.
Q. How did you feel on this diet in the beginning? Were you actually feeling good at the start of this program? And how long did you stay on this type of diet?
A. I felt fine in the beginning. I don't want to say I felt great, but I felt normal. Energy levels were ok, but I would often suffer low blood-sugar levels and feel like utter crap. Didn't notice any big difference from consuming BP coffee (unlike Joe Rogan, who said he "wanted to kick an alligator in the dick" after drinking BP coffee).
I stayed on the diet from August 2012 to May 2013.
Q. You mentioned that you were eating a lot of protein and fat? Was most of this coming from meat? Or were you also ingesting supplemental proteins and various oils?
A. Meat consisted of grass-fed beef, wild-caught salmon or other fish, pastured chicken, and eggs. Maybe tuna fish now and then. Whey protein every morning in my coffee. I also had salads quite a bit with EVOO and took cod-liver oil daily.
Q. You mentioned that you felt this diet led to some serious health issues. Can you describe those?
A. After a few months my cognition began declining, and in fact I started getting brain fog. My performance at work was slipping and I could barely tread above water.
I got blood work done. My cholesterol shot up by 70 points in three months. The other thing that was disturbing was that my inflammation marker (c-rp) was way above normal. This corroborated with how I was feeling, which was achy a lot. I was 34 and thought that this is what happens when you get older, but man I was shocked how quickly I was aging.
The thing that did it for me was that I started witnessing shortness of breath. Like I was about to pass out from shortness of breath. I first noticed it skiing (which I do a ton of and never had an issue), but then it began translating into normal everyday routines, like climbing stairs or riding a bike at a leisurely pace. When I would go to the gym and do squats and kettlebell swings, I would have to concentrate on breathing otherwise everything would go white.
I obviously was really concerned I had a heart defect, so I went to multiple specialists. Pissed away lots of money. They also said that I was normal. But I just felt awful and basically felt I couldn't do strenuous activity anymore, otherwise I'd die. I thought that this was going to become my new life or non-strenuous activity.
Q. And you can't think of anything else that might have caused these issues?
A. See answer above. PCP and cardiologist cleared me of any health problems. Once I ceased the above-described diet and starting ingesting normal foods, especially carbs, my shortness of breath went away. I had been suffering from insulin resistance since June of last year, but that has slowly been going away as well. I've noticed that my thinking the last few months has become much clearer.
Q. What made you finally pull out of that style of eating? And how did you know "it was time."
A. Thinking that I was going to die. I'm not kidding. When you can't even climb a flight of stairs without everything turning white and your heart's pounding in your chest, you know something's seriously wrong.
Q. How are you eating now and how improved are you? Some of the guys would probably be interested in knowing how long it took you to recover.
I eat a normal breakfast now, at least normal to me: a few eggs, lentils and some sauerkraut with tea. Or a smoothie with 40g Hi-Maize resistant starch, berries, flax seed, pea protein, and almond milk. I won't hesitate to eat pancakes or Muesli.
I generally eat salads during lunch, but won't hesitate to ingest some carbs, but clean carbs like quinoa, rice, legumes, or buckwheat. Dinner I usually let go and will eat pasta or a cooked potato. I'm eating fruit again! I love fruit. I eat a lot less meat and a lot more vegetables given that I'm basically substituting clean carbs for animal protein.
My bf% is now probably 16%. I don't love what I see in the mirror, but my girlfriend doesn't care, and frankly, I just want to feel good.
I still have not recovered 100%, even though I stopped this diet almost a year ago, although I've improved quite a bit. My cognition and memory have improved a lot, but I had to tackle the insulin resistance that had developed first. I believe my thyroid got screwed up from that diet because I've been suffering from libido, erection and insulin issues over the last year. I had a hemorrhoid for over eight months, which finally went away once I began jogging again and drinking pomegranate juice on a regular basis.
The biggest thing is the breathing. I think this diet really hammered my vascular system. I skied my butt off this past season w/o any issues. I've been climbing mountains the last few months, and no scary moments! I jog regularly for 30 minutes.
I'm still not great at the gym and do get dizzy when I do squats. It's like I've still maintained my strength, but my lungs/vascular system is lagging behind, and I get close to passing out. I hesitate going to the gym sometimes now (like today!) because I'm fearful of passing out, even though it hasn't happened (yet). I'm thinking of drinking beet juice before hitting the gym to ensure that I have adequate oxygen until this problem goes away.
Hope this helps everyone out there. I would really steer clear of low-carbing given what happened to me.
1) Nutr Metab (Lond), 2011, 8:75, "Is there a role for carbohydrate restriction in the treatment and prevention of cancer?"