I eat a Low Fat Diet and love it. I am currently eating a low fat, whole foods lacto ovo vegetarian diet. One thing that I have noticed is that Low Fat now is extremely unpopular right now with men, at least here in the U.S. As far as I can tell, Paleo and Low Carb fans have almost completely taken over the American health universe. And, because of this, I have heard time and again of all the dangers of low fat and how low fat eating is responsible for all of our health ills, etc. The latter accusation is ridiculous, of course, because so few American eat a Low Fat Diet. I personally do not know anyone who eats a Low Fat Diet and I doubt most of you do either.
Anyway, most of the objections that you hear about Low Fat Diets are just silly. But a few require serious consideration and I believe we can lump them into five general categories, which I summarize below:
1. Increased Arteriosclerosis. Dr. William Davis is one of the leading clinicans practicing plaque reversal and author of the popular book Track Your Plaque. He is probably the most popular speaker and writer that I know of in the cardiovascular arenta and has popularized his own flavor of reversing arteriosclerosis that has moved away from of the previous low fat-based techiques used by, say, the well-known Dr. Ornish. In fact, Dr. Davis is openly critical of Low Fat Diets and clearly states that some people will acclerate their plaque on a Low Fat Diet, not reverse it.
Now this is definitely a controversial assertion, because Dr. Dean Ornish showed in his studies that Low Fat Diets could reverse plaque. In fact, it was Dr. Ornish who really popularized the notion. Critics note, however, that participants in Dr. Ornish's studies underwent some weight loss and almost any diet can reverse plaque during weight loss. In fact, one recent study showed just that by putting participants on a low fat, low carb or Mediterranean Diet and all of them reversed IMT plaque approximately equally.  (IMT is intima-media thickness, i.e. the amount of plaque in the neck artery.) So any arterial study needs to show success under weight maintenance conditions to truly be valid.
However, let's go back to Dr.Davis' assertion that in some men a Low Fat Diet is a foe rather than a friend and may actually add arterial plaque instead of reversing it. The reason, according to Dr. Davis, is that low fat usually means high carbs and high carbs for some men means that their lipid profile will switch to the deadly "pattern B" mode. Pattern B is simply when your cholesterol profile has a greater percentage of atherogenic small LDL particles and increased triglcyerides.
REBUTTAL: Prior to Dr. Davis, there were a couple of huge clinician researchers that were well-established in plaque reversal: Drs. Esselstyn and Gould. Both of these researchers used Low Fat Diets as the base of their treatment strategy. Dr. Esselstyn is part of the Cleveland Heart Clinic and is world renowned in his research on reducing arterial plaque and author of a back entitled Prevent and Reverse Heart Disease. His formula is pretty simple: 
What Dr. Esselstyn did was to follow his patients for five years. And keep in mind that all of his patients were heart disease pateints. Dr. Esselstyn found that those that did not follow his program had an average of close to 4 cardiac events in five years on average. It means that these patients had one case of angina, a heart attack, or maybe a stroke on average about every year and a quarter. The contrast between those who did follow his program was striking: they had NO cardiac events. (There was one arrhythmia case which could not be attributed to diet.) In other words, Esselstyn's Low Fat Diet program gave these heart patients back their life and made them essentially free from heart disease.
And, wait, it gets better: arterial examinations showed that ALL of the complaint patients arrested their heart disease and three fourths of them reversed it!  Now how many guys that have erectile dysfunction need to reverse plaque? Well, I don't know what percentage, but it's got to be a big percentage. This is verified by the fact that the research shows that the average man has some kind of a cardiac even five years after his first signs of erectile dysfunction. And the reason is simple: you can have quite a bit of plaque in a neck or heart artery and not suffer from a heart attack or angina initially. However, that same plaque in your penile arteries will cause you substantial erectile dysfunction. Once those penile arteries are covered in plaque, nitric oxide levels go down significantly.
And one last comment: this is where the work of Dr. Gould comes in. Dr. Esselstyn only reversed arterial plaque in three quarters of his patients. However, Dr. Gould was able to reverse it in virtually everyone by putting them on a Low Fat Diet and coupling it with a statin. This is very impressive to say the least, because heart patients often only have a few more years to live and this essentially allows them to gain back decades of their life by reversing arteriosclerosis. I know many people do not like statins and I don't either - see my page on The Dangers of Statins - but for those with arteriosclerosis, this is a critical situation.
As a side note, I actually feel that this is what happened to me. In my late 40's I developed a significant amount of erectile dysfunction after years of a fast food and questionable eating habits. I also had had decades of low testosterone - something you can read about in My Personal Health Story - and low T is known for leading to hardening of the arteries. I tried consuming coconut oil and diets that I modeled after the Tokeluau and Pukapuka. These are essentially classic Paleo Diets and they simply did not work for me - quite the opposite. I got immediate relief, though, from eating Low Fat. And here is my point: I had a Heart Scan, also called a Calcium Score, in 2013 and they found that my cardiac arteries were perfectly clear! Basically, I had apparently cleared out all the arterial plaque from the decades previous through eating Low Fat, something you can read about in my page My Heart Scan Results.
2. Vitamin E. One of the criticisms of Low Fat Diets that you quite often hear is that fat in the diet is required to trigger the release of bile from the liver and, therefore, those that consume a Low Fat Diet could be deficient in Vitamin E. For example, children who have blocked or missing bile ducts can become Vitamin E deficient and require supplementation.  Furthermore, low fat critics often state that other fat soluble vitamins (A, D and K) may be poorly absorbed in a low fat environment.
REBUTTAL: A "Low Fat" Diet is really not low fat. Even the most strict Low Fat Diet is around 10% of calories as total fat. So, if a man consumes 2,500 calories in a day, 250 calories would be from fat. This translates to 28 grams of fat, which is a significant amount of fat. I know of no evidence that those eating Low Fat Diets have been shown to be deficient in any of the above vitamins. If this was an issue with Low Fat Diets, it would have been exposed years ago. And consider this:
Wild game is around 10% fat. Most of the plant foods that we eat are around 10% fat. Furthermore, the supercultures with the greatest longevity and nearly impeccable health records eat in the 10-20% fat range. How can the healthiest cultures on planet earth all be deficient in vitamins A, E and K?
And, if you are concerned about it, simply raise your fat levels to 15%. I have never eaten a pure 10% and have somehow managed to clear out my arteries for example. But raising your fat levels to 15% will add another another 14 grams of fat per day. This allows for a few nuts or some dressings/sauces that can really add flavor to what you are eating.
3. Your Cholesterol Will Be Too Low For Your Brain's Needs. The human brain needs a large amount of cholesterol and I have seen stats that about a quarter of all the body's cholesterol is between our ears. Based on these observations, some say that a Low Fat Diet will lead to cognitive, memory and psychological issues due to lack of proper supply of cholesterol. Other similar criticisms come from the fact that pregnenalone, a key brain hormone, is synthesized from cholesterol (LDL specifically) and, so the thinking goes, low cholesterol will lead to deficiencies here as well. Adding fuel to the fire was the fact that a mortality study showed that low cholesterol levels were correlated with an increased risk for possibly non-heart disease deaths and possibly suicide.
REBUTTAL: The body manufacturers virtually all the cholesterol that we need. We simply do not need to add cholesterol to our diet or eat a lot of fat to artificially inflate cholesterol levels. And think about this:
The Father of the Modern Paleo Movement is a researcher named Loren Cordain. One of his earlier research projects was a study of all the primal cultures in the world. His motive was to document how these ultrahealthy cultures ate and one thing that he found would shock most modern Paleo folks: EVERY culture had cholesterol below 150.
Of course, this hurts the you-gotta-have-beefy-cholesterol theories. If every one of our healthiest cultures has cholesterol below 150, then how can low cholesterol be unhealthy? In fact, couldn't it be argued that low cholesterol is actually the most brain healthy way to live? After all, in these cultures dementia and Alzheimers is unheard of. One of the low fat researchers has uncovered a significant body of evidence that increased levels of saturated fat is associated with Alzheimer's risk.  And the extra fat in our diet is likely a root cause of many migraines. Researchers explained that "a review of the literature indicates that high levels of blood lipids and high levels of free fatty acids are among the important factors involved in triggering migraine headaches. Under these conditions, platelet aggregability, which is associated with decreased serotonin and heightened prostaglandin levels, is increased. This leads to vasodilation, the immediate precursor of migraine headache. A high-fat diet is one factor that may directly affect this process."  This study put migraine-suffering women on a Low Fat Diet and they experienced significant relief.
As far as the supposedly negative mortality studies, Dr. Gould explained:
"In these large population studies, there is a small percentage of people who have preexisting medical conditions, such as cancer, depression, alcoholism, gastrointestinal disease, or addictive behavior such as drug addiction or smoking, all of which reduce appetitie and may impair nutrition in association with very low cholesterol levels. These preexisting conditions not only lower cholesterol levels but may also cause death unrelated to cardiovascular disease. Therefore, in such studies, there may be an association between death caused by the preexisting nonvascular disease and low cholesterol levels. However, if the people with these preexisting nonvascular medical conditions are screened out and removed from the analysis, there is no increase in deaths associated with low cholesterol levels." 
4. Weight Loss is Harder. One third of all men in the U.S. are overweight and one third are obese. So weight loss is a big issue in most Western countries. When a guy is 40 or 50 pounds overweight, he wants to lose weight and lose it quickly. One study shows that low carb diets are the fastest way to lose weight. Anecdotally, many men have reported that this is true, assuring its superstardom in the health world.
REBUTTAL: Low carb diets cause rapid loss of liver glycogen stores, which are bound up in a bunch of water. When someone loses weight via low carb, there is an initial rapid burst of water loss on top of the regular weight loss. Atkins himself admitted this was a huge problem, because the minute that the dieter starts adding in carbs again and increasing glycogen stores, the water weight comes right back on.
Plus, Low Fat Diets have the huge advantage of weight loss without suffering. Okay, that's a slight exaggeration, but higher carb diets tend to have much greater volume and bulk than high fat diets. This allows a man to eat until his stomach is largely full and thus feel minimal hunger. Example: a large baby carrot is about 5 calories. To even get 200 calories, one would have to eat 40 baby carrots! If you do a Low Fat Diet correctly, you can lose weight almost effortlessly. Yes, that's part of the reason that a lot of Asian peoples are thin.
5. Carb Intolerance. There is a school of thought out there now that some men are "carb intolerant," i.e. simply cannot handle carbs any more. The backbone of this theory is that some men have essentially entered the prediabetic, Metabolic Syndrome stage and even moderate carbs will give them fatigue, brain fog and, in some cases, high blood pressure. Phil Maffetone, the overtraining expert, and others have two week carbohydrate intolerance tests out there to see if you are in this category.
REBUTTAL: Perhaps this is the case for some men. However, consider if the following five criterion were met:
a) all simple carbohydrates including wheat were avoided
b) fructose was limited to 50 grams per day or less
c) testosterone levels were maintained at youthful levels
d) all carbs were low glycemic (non-wheat whole grains, legumes, beans, etc.)
e) exercise was at least an hour per day
Of course, a man with testosterone of 400 ng/dl is going to struggle: low testosterone raises insulin levels. But how many men with youthful T levels who are exercising an hour per day need lower carbs?? I'm sure it happens, but my experience is that most men who have youthful health and hormones have youthful appetities and metabolisms based on what I have seen on The Peak Testosterone Forum.
And one other important comment: Dr. Neal Barnard has a book on reversing diabetes and he directly addressed this issue by doing a study of men with high A1C placed on a low glycemic, Low Fat Diet. The high carbs made these diabetics worse, right? Actually, the results were impressive and the opposite: he found that he could lower their A1C as much as medication even though the men were eating a high carb diet. I discuss all of this in a page on Low Fat and Diabetes. Remember that insulin resistance is caused by the buildup of lipids (fats) within the cells and a Low Fat Diet, even though it is high carb, greatly helps this process.
1) Circulation, 2010, 121: 1200-1208, "Dietary Intervention to Reverse Carotid Atherosclerosis"
3) Am J Clin Nutr, 1984 Aug, 40(2):246-50, "Serum vitamin E levels in children with corrected biliary atresia"
5) J of Women's Health and Gender-Based Med, May 7 2009, 8(5), "The Influence of a Low-Fat Diet on Incidence and Severity of Migraine Headaches"
6) Heal Your Heart: How You Can Prevent or Reverse Heart Disease, Dr. K Lance Gould, M.D., p. 67.