Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association With Genotype Pattern or Insulin Secretion-The DIETFITS Randomized Clinical Trial

The study aimed to determine the effect of a sound low-fat diet, compared with a solid low-sugar diet on weight changes, and to find out whether genotype outlines and insulin eliminations are associated with food intake routines on weight changes. The study employed a total of 600 adults who hailed from the San Francisco and California areas. The study procedure involved a one-month program whereby participants were encouraged to stick to their routine diet type, maintain a moderate exercise and a leveraged body weight. Data was collected during the study on each 3rd, 6th and 12th months respectively from all categories where it was possible.

Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight
Adults and the Association With Genotype Pattern or Insulin Secretion-The DIETFITS
Randomized Clinical Trial
BY
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Briefly summarize the nature, aims and hypothesis/es of the study.
The main objective of this study was to determine effect of a sound low-fat diet,
compared with a solid low-sugar diet on weight changes, and to find out whether genotype
outlines and insulin eliminations are associated with food intake routines on weight changes,
Gardner et al (2018).
The hypotheses of the study were two. The first hypothesis stated that there is food intake
routine and genotype outline correlation that impacts weight reduction. The second hypothesis
stated that there was a correlation between diet and insulin that could impact on weight
reduction.
Summarize the methods used in the study, including participants, materials and basic
procedure.
The methods used in this study include the participants, materials and the basic
procedures that were followed. The study employed a total of 600 adults who hailed from the
San Francisco and California areas. The participants were sought after through advertisements in
the media and through email lists, Zhao et al (2016). Men and women of between 18-50 in the
pre-menopausal stage and having body mass index of between 28 and40 were considered in the
study. Individuals with hysteric hypertension or diseases as cancer and diabetes, among others,
were excluded from the study. Other exclusion criteria was pregnancy and lactation for women.
Randomization to get sample population for the two study classes (sound low-sugar
eating routine and a solid low- fat eating routine), was done using a mechanized arbitrary
generation mechanism). There was a total of 8 class sizes, with each class having 4 members.
The first study was limited by finances and could not therefore involve the entire sample.
In that case, the investigation only included a 2×2 factorial outline (abstain from food ×
genotype-design coordinating). However, just as the study was beginning, there was more
funding, up to twice the original funding. This made it possible for an increase of 50% of the
sample population size. This allowed for the study involving the second sample category

(evaluation of a count calories × insulin emission connection) to begin. It also allowed for a
larger pact of measurements to be available.
The study procedure involved a one-month program whereby participants were
encouraged to stick to their routine diet type, maintain a moderate exercise and a leveraged body
weight. The study involved a total of 22 learning lessons which were carried out over a 12 –
month period in the diet-specific groups which had an approximate of 17 members. Classes were
held every week over a period 0f two months, then after every two weeks for eight weeks, then
for three successive weeks on up to the 6th month, and thereafter on a monthly basis. Lessons
were facilitated by 5 trained and seasoned health educationists, Wang et al (2012). Each one of
the trainers taught one category from each main sample classes. Participating members were
advised to given procedures and guidelines, including sticking to the provided diet
recommendations and exercise sessions. They were further encouraged to set goals to embrace
self-drive as part of the behavioral change mechanisms.
Detail the main findings of the study and whether the hypothesis was supported.
Data was collected during the study on each 3rd, 6th and 12th months respectively from all
categories where it was possible. The dietician who took measurements were not required to
know the diet measurements, genotype outlines or food delineations. Gross energy usage
distribution was measured by using a special questionnaire for seven days. Diet consumption and
physical activities were measured by the participants’ self-reporting mechanisms. Weight
measurement was also carried to monitor a 12 – month outcome, Davies et al (2014).
Genotype characteristics and insulin eliminations were monitored for testing and were
analyzed using scientific approaches and analyzed mathematically.
Out of the maximum 27 possible outcomes, only 15 were observed with a one percent
more frequency in the originally observed samples for adults. The genotypes were grouped in
two classes: those that had more affinity to sugar and those that had higher affinity to neither
genotype patterns.

In relation to Rosenfield (2009), During each of the 6th and 12th months, sugar tolerance
examination was carried out for each participant that was set at 75g. The study results showed to
indicate that a type of insulin-elimination measuring formula (INS-30) could be successfully
used to predict weight-loss in low-sugar food-intake routines. It was also observed that early-
insulin removal varied between various foods intake routines.
In the 609 participants, 573 women, making up 57% had low-sugar genotype and 244
while 244 had low – fat intake genotype. This were the original characteristics of the sample
size. After the study, the results were as is outlined below. Out of those who were in the sound
low-fat food intake routine category, 130 participants were observed with low-sugar genotype,
which makes up 42%. Out of those in the sound low-sugar category, 114 participants were
observed with low-fat genotype making up 38%, and 97 were observed with low-sugar genotype,
making up 38%, Levran et al (2008).
Out of the 22 class categories that makes up the total study sample, the number of classes
attended, calculated to the nearest mean was 14.4 for the sound low- fat food intake routine
category. For the sound lo-sugar food intake routine category was 14.6, including those who
dropped on the way.
Only 79% of those wh0 attended the full sessions gave out complete data as was required.
Health education willingness and material knowledge was generally high and uniform for both
categories.
The total energy consumption was not so much variant between the categories at any
time. At base level, insignificant changes in monitored nutrients were observed between the
groups.
In weight-loss, the weight change was a -5.3 kg for the sound lo-fat diet intake routine
category while for the sound low-sugar food intake routine category was 6 kg. It is noted that the
weight change results are not so much statistically spread apart. A uniform weigh-change trend
of 40 kg was observed across the categories, Tazaki et al (2016).

Insignificant variations in weight change were noted in interaction monitoring. There was
not much differences in weight-loss amongst the participants. From an analysis done that only
composed no-European descents only, no much genotype interactions were observed by
genotype outline.
For secondary outcomes, significant improvement was noted for the two categories. For
body mass index, percentage fat and waist size measurements, there were no major differences
noticed between the two categories. After the elapse of the 12 months, there was noted decrease
in high blood pressure, and diabetes indications lowered as insulin and glucose levels dropped.
There was only one exception – an increase in cases of cholesterol levels (rightly known a low
density lipoprotein cholesterol (LDL)) in participants of the sound low-sugar food intake routine
category. This was however not observed in the lo-fat food intake routine category, Zhang et al
(2012).
Respiratory trade proportion was noted to be insignificant between the two categories but
a little low for the sound low-sugar food intake routine category as compared to the sound low-
fat food intake category, Tazaki et al (2016). Energy at rest between the two groups was not so
much variant between the categories during the 6th and 12th months, although a significant
decrease was noted at base level for the two groups. Gross energy consumption rate was not
variant between the two groups, Tazaki et al (2016).
Identify potential threats to internal and external validity in the research design.
Potential threats internal validity
Instrumentation – changes in the measuring instruments that would be used in the study
or the criteria for sampling the population is a potential threat to the validity of this study. On the
same note, changes in the standard measurement of concentrations for insulin and glucose would
have an immense impact on the overall findings, Seheri et al (2010).
Mortality – despite the fact that study involved participants enjoining themselves in the
exercise out of their own will, there are chances of drop out cases. This will of course alter the
sample size and this would greatly impact the validity of the study since this is a study with a
long timeline.

Maturation - as is normal with human beings, the level of concentration and general
performance decreases with time. It could be the case that fatigue of doing repetitive tasks would
result to indifference amongst the participants, dietitians and trainers within the 12-month study
timeline. This would impact subsequent results.
External Threats
Experiment interference – this can happen in the case when participants go through the
same experimentation multiple times. In that case effects may be carried over to on subsequent
tests hence can lead to vague results. There would be a tendency to generalization of results.
Exclusion and Inclusion Criteria: the sample selected, for example the selected sample
was from Francisco and California areas may not fully represent the entire population, hence
they may not capture the envisaged characteristics.
Reactions to experiment setup - this would be the case in this study since it takes a
long time and participants could be too much familiar with the procedures to the extent that they
would be programmed to react to them naturally since they are aware of the experiments. This
would affect the validity of the study, Gardner et al (2018).
Conclusion
The study, it is observed that there were insignificant differences in weight-loss between
the two established classes. The genotype outlines and insulin eliminations did not in any way
associated with food intake routines on weight changes. The hypothesized factors were not of
any help in for determining a better diet for any group of people.
For inclusion of participants, there would have been a training process before they are
inducted into the study so as to discourage drop outs. The study timeline would have been
reduced so as to reduce fatigue and indifference cases amongst the participants. The participants
would have trained as part of the induction processes so as to avoid cases of dropping out.
The number of dietetics and trainers could have been increased to as to avoid or reduce cases of
multiple experimentation.

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