The world of nutrition is full of misinformation, conflicting information, and constantly changing information. One of the most controversial topics in nutrition is fat.
Is fat good? Bad? One of the problems with fat is that not all fats are created equal. There's saturated fat, monounsaturated fat, omega-6 polyunsaturated fat, and omega-3 polyunsaturated fat. Then each of these fats can come in different lengths.
Do you see how this can get confusing?
I'd like to tackle saturated fat in this article as it has the most jaded history.
Saturated fat is deemed such because it's fat that it is full, or saturated, with hydrogens while monounsaturated and polyunsaturated fats have "open spaces" that aren't filled by hydrogens.
As previously mentioned, fats can also come in different lengths. The saturated fats mainly found in coconut oil, lauric acid, are shorter in length than the stearic or palmitic acid commonly found in meats and other plant products.
Coconut oil is very interesting as it's gained a reputation of being the "good" saturated fat with potential benefits ranging from antimicrobial to cardioprotective. I'm personally not convinced of the magical properties of coconut oil but do regularly use it in my meal plans (as it tastes great).
Regardless of what the pro-saturated fat people may try to convince you, too much saturated fat can be a bad thing. Increased saturated fat intake has been consistently shown to increase LDL cholesterol (the "bad" cholesterol).
Below is a figure from the 2005 Dietary Reference Intake report that shows this relationship. As mentioned before, lauric acid (found in coconut oil) may have certain benefits over other saturated fats. Grudy et al(1) showed that compared to palmitic acid causes a smaller increased in LDL cholesterol.
Saturated fat not only increases LDL-C but it increases HDL-C (as well). In fact, saturated fat has been shown to be a key component in maintaining elevated HDL-C levels as studies have shown that when replaced with unsaturated fat or carbohydrates, HDL-C will decrease.
If things couldn't get more confusing, a recent study in the American College of Cardiology showed the increased levels of saturated fats potentially inhibit the anti-inflammatory effects of HDL-C(2). Increased intakes of saturated fat have also been correlated to increased rates of colon cancer.
The good news is that as a bodybuilder you're probably taking in a limited amount of saturated fat to start out, so I'm not asking you to decrease your saturated fat intake. In fact you might benefit from increasing your saturated fat intake(3).
Let's look at a sample meal plan
- 9 Egg Whites
- 2 Whole Eggs
- 2 Cups Cooked Oatmeal
- 1.5 Scoop Metabolic Drive®
- 1oz Almonds
- 1 Medium Apple
- 6oz Chicken Breasts
- 2 Cups Broccoli
- 1 TBSP Olive Oil
- 1 Scoop Metabolic Drive®
- 1/2 Cup Cottage Cheese
- 1 TBSP Peanut Butter
- 6oz Chicken Breast
- 1 1/4 Cups Rice (Pre-Cooked Measurements)
- 1 TBSP Olive Oil
- 2 Cups Spinach
- 6oz Top Round Beef
- 4 Cups Spinach
- 1/2 Cup Cherry Tomatoes
- 1 TBSP Olive Oil
- 1/2 Cup Cottage Cheese
- 2 TBSP Peanut Butter
This meal plan is about 3,700 calories with 27% of calories coming from fat. But only 6% of the calories are from saturated fat. This is definitely on the low side. Even the National Cholesterol Education's set's the upper limit for saturated fat intake for people at risk of CVD at 7%. As a healthy, active, weight pumping individual you can afford to eat more saturated fat as it may raise your Testosterone levels.
So will eating more saturated fat increase your Testosterone levels? Male vegetarians have been shown to have lower levels of plasma Testosterone compared to their meat eating counterparts(4).
Vegetarians consistently consume lower levels of fat (total and saturated fat) compared to omnivores. Dorgan et al(5) randomly assigned 45 men to either a high fat/low fiber or a low fat/high fiber diet. The subjects followed each diet for 10 weeks. The high fat/low fiber diet periods yielded 13% higher levels of total serum Testosterone compared to the low fat/high fiber diet period.
From this data it's hard to determine whether or not it was the total fat or saturated fat that made the difference between diet groups because the high fat diet group consumed ~20% more calories from fat with ~10% of that being from saturated fat.
Previous work by Keys et al(6) found a correlation between higher levels of Testosterone and increased intake of polyunsaturated fat, so that's something that should be considered.
Another study completed in the early 80's(7) involved 30 healthy men (ages 40-49) who were placed on a diet for 6 weeks where 40% of their calories came from fat. This was followed by another 6-week period in which only 25% of their calories came from fat.
To determine the influence of saturated fat, the high fat diet had a polyunsaturated: saturated fat ratio (P:S) of 0.15 while the lower fat diet had P:S ratio of 1.22. At the end of the lower fat diet, the men had significantly lower serum total and free Testosterone levels. But because the low fat diet also had lower levels of saturated fat, the effect of total fat vs. saturated fat could not be teased out.
The above studies have all been longer term (6-10 weeks), controlled feed studies, but there's an acute treatment study that actually showed a 30% decrease in total and free Testosterone following a high fat meal. In this study(8), 8 men were given a shake contains 18 grams of protein, 50 grams of fat, and 67 grams of carbohydrates. Their blood was measured every hour for 4 hours.
It should be stated again that this study contained a small sample size but the results do suggest that it's not hormonally beneficial to consume large amounts of fat in one sitting, but rather spread it out across the day. Of course, I'm sure most of you aren't consuming 1/4 Cup of olive oil or 1/2 a stick of butter in one sitting (at least I hope not!).
Unfortunately, the researchers never stated what types of fats were found in the shake as this would have been useful information.
The final two studies that we will look at are probably most relevant to the T-Man. This study enrolled 8 strength athletes and 10 active non-athletes(9).
Upon comparison of the subject's dietary analyses and blood tests, it was found that only the strength-training athletes had significant correlations between fat intake and Testosterone levels. That means, if you lift weights and eat a diet higher in fat, then you'll receive the benefit of elevated Testosterone levels compared to if you were just "active" and ate a higher fat diet.
Unfortunately, again, the sample size is small. As a side, the researchers also found a negative correlation between protein intake and Testosterone levels (i.e. consuming too much protein leads to decreased T).
So beware of having too much of a good thing. Volek et al(10) conducted a similar study in which they compared the dietary records and blood tests of 12 men with at least one year of weight training. The researchers found significant correlations between Testosterone levels and total and saturated fat intake.
After reviewing the literature and studies presented in this article, one can't say that increased consumption of saturated fat definitively increases Testosterone levels, but it may, especially in strength training individuals. It's evident, though, that a higher total intake of dietary fat (30-35% of calories) does increase Testosterone levels compared to a low fat diet.
So grab an avocado, slather it with butter and enjoy!
- Grundy SM. Influence of stearic acid on cholesterol metabolism relative to other long-chain fatty acids. Am J Clin Nutr. 1994 Dec;60(6 Suppl):986S-990S.
- Nicholls SJ et al. Consumption of saturated fat impairs the anti-inflammatory properties of high-density lipoproteins and endothelial function. J Am Coll Cardiol. 2006 Aug 15;48(4):715-20.
- Volek JS et al. The case for not restricting saturated fat on a low carbohydrate diet. Nutr Metab (Lond). 2005 Aug 31;2:21.
- Howie BJ et al. Dietary and hormonal interrelationships among vegetarian Seventh-Day Adventists and nonvegetarian men. Am J Clin Nutr. 1985 Jul;42(1):127-34.
- Dorgan JF et al. Effects of dietary fat and fiber on plasma and urine androgens and estrogens in men: a controlled feeding study. Am J Clin Nutr. 1996 Dec;64(6):850-5.
- Key TJ et al. Testosterone, sex hormone-binding globulin, calculated free testosterone, and oestradiol in male vegans and omnivores. Br J Nutr. 1990 Jul;64(1):111-9.
- Hämäläinen EK et al. Decrease of serum total and free testosterone during a low-fat high-fibre diet. J Steroid Biochem. 1983 Mar;18(3):369-70.
- Meikle AW et al. Effects of a fat-containing meal on sex hormones in men. Metabolism. 1990 Sep;39(9):943-6.
- Sallinen J et al. Relationship between diet and serum anabolic hormone responses to heavy-resistance exercise in men. Int J Sports Med. 2004 Nov;25(8):627-33.
- Volek JS et al. Testosterone and cortisol in relationship to dietary nutrients and resistance exercise. J Appl Physiol (1985). 1997 Jan;82(1):49-54.