Here are two studies that shows it doesn't really matter what kind of diet you're on. All that really matters is energy deficit.
1: http://www.ncbi.nlm.nih.gov/pubmed/16476868
BACKGROUND:
Low-carbohydrate diets have become increasingly
popular for weight loss. However, evidence from individual trials about
benefits and risks of these diets to achieve weight loss and modify
cardiovascular risk factors is preliminary.
METHODS:
We
used the Cochrane Collaboration search strategy to identify trials
comparing the effects of low-carbohydrate diets without restriction of
energy intake vs low-fat diets in individuals with a body mass index
(calculated as weight in kilograms divided by the square of height in
meters) of at least 25. Included trials had to report changes in body
weight in intention-to-treat analysis and to have a follow-up of at
least 6 months. Two reviewers independently assessed trial eligibility
and quality of randomized controlled trials.
RESULTS:
Five
trials including a total of 447 individuals fulfilled our inclusion
criteria. After 6 months, individuals assigned to low-carbohydrate diets
had lost more weight than individuals randomized to low-fat diets
(weighted mean difference, -3.3 kg; 95% confidence interval [CI], -5.3
to -1.4 kg). This difference was no longer obvious after 12 months
(weighted mean difference, -1.0 kg; 95% CI, -3.5 to 1.5 kg). There were
no differences in blood pressure. Triglyceride and high-density
lipoprotein cholesterol values changed more favorably in individuals
assigned to low-carbohydrate diets (after 6 months, for triglycerides,
weighted mean difference, -22.1 mg/dL [-0.25 mmol/L]; 95% CI, -38.1 to
-5.3 mg/dL [-0.43 to -0.06 mmol/L]; and for high-density lipoprotein
cholesterol, weighted mean difference, 4.6 mg/dL [0.12 mmol/L]; 95% CI,
1.5-8.1 mg/dL [0.04-0.21 mmol/L]), but total cholesterol and low-density
lipoprotein cholesterol values changed more favorably in individuals
assigned to low-fat diets (weighted mean difference in low-density
lipoprotein cholesterol after 6 months, 5.4 mg/dL [0.14 mmol/L]; 95% CI,
1.2-10.1 mg/dL [0.03-0.26 mmol/L]).
CONCLUSIONS:
Low-carbohydrate,
non-energy-restricted diets appear to be at least as effective as
low-fat, energy-restricted diets in inducing weight loss for up to 1
year. However, potential favorable changes in triglyceride and
high-density lipoprotein cholesterol values should be weighed against
potential unfavorable changes in low-density lipoprotein cholesterol
values when low-carbohydrate diets to induce weight loss are considered.
2: http://www.ncbi.nlm.nih.gov/pubmed/18025815
BACKGROUND:
This study was designed to compare the effects
of 2 different but isocaloric fat reduction programs with the same
amount of energy deficit - diet alone or diet combined with aerobic
training - on body composition, lipid profile and cardiorespiratory
fitness in non- or moderately obese women.
METHODS:
Twenty
non- or moderately obese (BMI 24.32 +/- 3.11) females (27.3 +/- 6.6
years) were tested at the beginning and after an 8-week period of a mild
hypocaloric diet for the following parameters: (1) body mass and body
fat; (2) total cholesterol, HDL-C, LDL-C and triglycerides; (3) lactate
(millimol/liter) during submaximal exertion (100 W); (4) heart rate
during submaximal exertion (100 W), and (5) maximum exercise performance
(watt). Subjects were randomly divided into either a diet alone (D,
-2,095 +/- 659 kJ/day) or a diet (-1,420 +/- 1,084 kJ/day) plus exercise
(DE, three 60-min sessions per week at 60% of VO(2)max or -5,866
kJ/week) group.
RESULTS:
Body mass and body fat decreased
significantly in D (-1.95 +/- 1.13 kg or -1.47 +/- 0.87%; p < 0.05)
and DE (-2.23 +/- 1.28 kg or -1.59 +/- 0.87%; p < 0.05), but there
was no significant difference observed between the groups. Statistical
analysis revealed no significant changes of total cholesterol, HDL-C,
LDL-C, triglycerides and heart rate during submaximal exertion (100 W).
Lactic acid accumulation during submaximal exertion (100 W) decreased
significantly (-0.8 +/- 1.4 mmol/l, p < 0.05) in DE and increased
significantly (+0.4 +/- 0.5 mmol/l, p < 0.05) in D. Maximum exercise
performance improved significantly (+12.2 +/- 8.8 W, p < 0.05) in DE
and did not change significantly in D.
CONCLUSIONS:
This
study showed that independently of the method for weight loss, the
negative energy balance alone is responsible for weight reduction.
What we can draw from this is purely for losing weight, your diet doesn't matter. It only matters in regards to health.
Calories in > x < Calories out