Intro:
To
achieve weight loss with any success, a calorie deficit is necessary. This
essentially means to consume less calories than you are expending, typically
over the time frame of a day. Although diet composition is debated to have an
effect on weight loss, most evidence generally shows little difference for
weight loss between different macronutrient breakdowns. This difference could
be exaggerated if we go to the extremes, such as with very low carbohydrate
diets. In which case there is a greater degree of water loss when removing
carbohydrates. Although most fitness professionals tend to agree that more
protein in one's diet is generally a good thing. This article shows how that
might not necessarily always be the case.
The Nitty-Gritty:
25
individuals between 18-35 were separated into 3 groups: a low protein group (5%
of diet from protein), normal protein (15% protein), or high protein (25%
protein). Upon completing a weight maintenance phase of about 2 weeks,
participants than were subjected to 8 weeks of over feeding with 40% greater
intake. All participants spent the duration of the study in a metabolic unit
and had food prepared for them. Participants were not subjected to any physical
activity or exercise.
What Happened / Results:
- All participants gained weight
with no significant differences between sex or race.
- Although, The Low protein group
gained on average 3.16kg
- Normal protein group gained
6.05kg
- High Protein group gained 6.51kg
- The difference? Lean body mass
(anything except fat/adipose tissue) was -0.70 in low protein, +2.87kg normal
protein, 3.18kg in high protein groups.
- Overeating caused resting energy
expenditure to increase for both the normal and high groups.
-Fat storage between groups was
insignificant. All three groups gained nearly the same amount of fat mass.
Takeaway:
Diet
composition could have an effect for body composition, weight loss, or
performance. Protein has a higher thermic effect than both fat or carbohydrate.
Meaning essentially that protein is converted to heat to a larger degree than
other macronutrients. This suggests that it would be potentially beneficial to
increase protein during dieting as it helps to preserve lean mass and promotes
satiety (feeling full) as well. It's important to remember not to exclusively
rely on the scale when it comes to weight loss. As some of these sedentary
subjects even gained some lean body mass. Although this study does not
differentiate how much of the increase was due to muscle, water, or bone mass.
Having a reliable method of assessing body fat during the weight loss process
can be very beneficial.
Bray GA, Smith SR, de Jonge L, et al. Effect of Dietary Protein Content on Weight Gain, Energy Expenditure, and Body Composition During OvereatingA Randomized Controlled Trial. JAMA. 2012;307(1):47–55. doi:10.1001/jama.2011.1918
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