Effect of Massing on Unsaturated fats or Saturated Fats on Body Composition

Time to mass up and we are faced with a selection of which macro to increase and once selected, what types of food from that macro to increase. For the purpose of getting swole my main concern is what is going to lay down the most muscle tissue possible. I could focus on protein or carbs, but I do want to throw a bone to the naughty stepchild dietary fats. Particularly if there is a certain type of fat that might have great hypertrophy outcome than other types. This won’t be a comprehensive review of the literature, but I came across an interesting study to dive in on massing with certain types of fats. This study will give new definition to the “muffin pump”!

Study:

Overfeeding Polyunsaturated and Saturated Fat Causes District Effects on Liver and Visceral Fat Accumulation in Humans

Purpose:

Investigate the effect of excess intake of omega 6 fatty acid linoleic acid (PUFA) or saturated fatty acid (SFA), Palmitic acid, on liver fat accumulation, body composition and adipose tissue gene expression.

Subjects:

39 healthy men and women, BMI 18-27 kg/m2, exercise and omega 3 intake were exclusion criteria.

Design:

Subjects assigned to eat a muffin containing either sunflower oil 9(unsaturated fat) or palm oil (saturated fat) over course of 7 weeks. FUN RIGHT! Researchers adjusted muffin intake to make sure subjects had a 3% weight gain.

Results:

Both groups gained 1.6kg in weight. The SFA group gained more liver fat, total fat and visceral fat. While the PUFA group gained more lean body mass, actually 3x the amount of lean body mass. Both groups ate at a 750-calorie surplus per day and protein intake was a nonsignificant difference at 14% of the diet. No changed in adipose tissue gene expression was seen between groups. The same rise in insulin resistance was seen in both groups as well.

Discussion:

So, let’s explain the potentials for more liver and visceral fat gain over lean tissue gain with SFA. PUFAs are more readily oxidized than SFA leaving fewer fatty acids available for liver deposition and less rise in triglycerides. Researcher in the study did not have a mechanistic explanation for the increased lean mass accretion in the study. Potential mechanisms may lie in increased cell membrane fluidity. Cell membranes serve as regulating passageway for nutrients, hormones and external stimuli. A less fluid membrane can impede these signals within the cell and limit cellular processes such as protein synthesis. More fluid membrane allows for improved permeability of nutrients, hormones, and signals for proper anabolic signaling. Of note as well the muffins contained high amounts of fructose and fructose in combination with SFA can enhance liver fat accumulation.

Takeaway:

1. Overfeeding on PUFA over SFA decreased liver and visceral fat gain and increased lean body mass 3x that of SFA.
2. This does NOT mean go mass on a bunch of muffins filled PUFA!
3. This does NOT mean never eat saturated Fat!!
4. We do NOT base our diets off of one study, this purely gives us some ideas of how different nutrients work.
5. Massing in general should still be primarily compromised of carbohydrate, followed by protein, and then lastly fat. The composition of that fat should primarily be coming from unsaturated fatty acids such as avocado, nuts, fish, plant/seed oils with a lesser extent from saturated fats such as butter, animal fats, coconut oil, palm oil.

Confused on fats, what question do you have for me?

Train Hard!

John Jewett MS RD
IFBB Pro

Reference: Rosqvist F, Iggman D, Kullberg J, et al. Overfeeding polyunsaturated and saturated fat causes distinct effects on liver and visceral fat accumulation in humans. Diabetes. 2014;63(7):2356-2368. doi:10.2337/db13-1622