Imagine if you could lose weight, improve your heart and overall health and still enjoy the foods you love. Well - technically, you always could. Weight loss is ultimately about creating a calorie deficit - either by exercising more or by cutting back on your daily calories, but we all know that consuming a large proportion of calories from fat is not generally advisable.
In addition to the negative effects of fats, especially those from meats, on the cardiovascular system, a high fat diet usually means less carbs, which include fruits and veggies, loaded with fibre, vitamins, minerals and antioxidants. This can also mean there will be less protein in the diet over all, and protein is necessary to keep muscles, the immune system and one's metabolism healthy. That's a big trade off.
But new research from Johns Hopkins University has shown that high fat, low carb diets may not have a negative effect on endothelial (blood vessel) function. In the study, one group followed a diet made up of 40% fat from nuts, seeds and meats, (which is higher than the advised 30% max), and 30% carbs (which is far lower than the minimum recommended 45%). Another group followed a low-fat diet of 30% fat and 55% carbs which are both actually at the high end of normal recommendations. This also means that the "high fat" group received 30% of their calories as protein, which is a good amount, but the "low fat" group received only 15% of their calories from protein, which is at the low end. Both groups also did cardio and strength training 3 times a week.
Both groups did equally well on tests of their blood vessel functioning, perhaps as a result of an overall reduction in calories (including fat) and exercising 3 times a week, but the high fat group lost weight faster. There is a pretty simple explanation for this - carbs hang on to water, and consuming 55% carbs and low protein means that there will be more weight on the body as water. The low carb, "high fat" group lost weight faster, but as soon as they start eating carbs again, that water weight will stick right back to them. Their more rapid weight loss is not likely true, permanent weight loss, which is fat loss. Moreover, they were consuming a lot of healthy fats from nuts and seeds and not only meats - it would be unwise for anyone to consume large amounts of saturated fats from meats as there is a strong association between these fats and heart disease.
One of the study's co-authors basically said the same thing in different words, saying ""Our study should help allay the concerns that...a low-carb approach does not seem to pose any immediate risk to vascular health,". The key word here is "immediate". She also warned that high fat meals are usually high in salt as well, which can lead to a dangerous situation for one's health. The bottom line is really about moderation - a moderate to low carb, moderate to high protein and regular to low fat diet is probably the best option, but everyone's body responds differently to various combinations and permutations of macronutrients. In this case, trial and error and balance are what it's all about. And yes, you can still enjoy some bacon here and there.