Protect, The impact of a high protein diet on the preservation of muscle mass during caloric restriction in overweight middle-aged to elderly people

Weight loss can have substantial health benefits in overweight and obese
adults. It is well established that caloric restriction leads to weight loss.
This weight loss is commonly accompanied with a reduction of lean body mass.
The loss of lean body mass with weight loss may have adverse outcomes such as
poor physical function, sarcopenia, deleterious metabolic consequences, and
frailty. It has been reported that high protein diets leads to a loss of body
weight and preservation of lean body mass in young adults. In middle aged to
older adults, however, the benefits of a high protein diet on muscle mass
preservation during caloric restriction is unclear.

To investigate the effects of a high protein diet vs. standard protein diet for
12 weeks on preservation of muscle mass during caloric restriction in
overweight and obese middle-aged to elderly people.

Randomized, controlled, double-blind, parallel-group intervention trial in
overweight and obese middle-aged to elderly people.
60 men and women of 55-70 years will be included and followed for 12 weeks.
Muscle mass iwill be measured at the beginning and at the end of the dietary
intervention. After baseline measurements, participants will enroll into the
run-in week to get aquinted study procedures and to achieve weight/energy
balance. During the run-in week, all foods will be supplied. After the run-in
week, subjects will receive a diet which is completely supplied by the
university.
To investigate the effect of a high protein diet compared to a standard protein
diet, the participants are at random divided in 2 groups, namely:
1. High protein diet with caloric restriction
2. Standard protein diet with caloric restriction

All subjects consume a caloric restricted (25%) diet for 12 weeks. Subjects are
at random divided in 2 groups:

1. High protein diet with caloric restriction
30% protein, 40% carbohydrates, 30% fat
1.5 g/kg BW/d protein

2. Standard protein diet with caloric restriction
15% protein, 55% carbohydrates, 30% fat
0.8 g/kg BW/d protein

Burder in time:
- Screening: 2 hours
- 2 days of measurements of 4 hours, 2 days of measurements of 1 hour
- diner every weekday: 30 minutes a day
Total: 45 hours


Benefits
The subjects will receive a final report of the test that will be performed. In
this report, their own results will be presented. Moreover, the final group
results will be presented. Participants are free to withdraw from further
participation for any reason and at any time during the trial. After full
completion of the study, the participants will receive ¤200, excluding travel
costs. A total of ¤50 or ¤100 will be provided to compensate for the travel
cost (¤50:<5km and ¤100: >5km). In addition to the *cash-reward*, during the 13
weeks of the study, subjects receive all their foods and drinks for free (~8.5
Euros a day x 91 days = 773 Euros). Besides this, the participants will have
dinner in a group, which also has a social aspect. The participants are able to
maintain their daily activities. And finally, during this intervention, the
subject may benefit from losing weight under professional supervision, which
might result in health benefits.

Risks
The risks involved in participating in this experiment are minimal. A catheter
is comparable to a normal blood drawn and the only risk is that of a small
local hematoma. In total, 140 ml blood will be collected throughout the entire
intervention. No noticeable effects will be expected. The incision made for
obtaining the muscle biopsy will be done by an experienced physician and will
heal completely. The meals for this study are made from normal nutritional
ingredients and are not expected to bring any health risks. The physical
measurements (1RM, SPPB, 400m, handgrip strength) can result in feelings of
muscle soreness.
The voluntary adipose tissue biopsy will be performed by an experienced
physician and will heal completely. It can occasionally cause a local haematoma
or bruise and some participants may report pain or discomfort.