Effects of Identical Weight Loss on Body Composition and Features of Insulin Resistance in Obese Women With High and Low Liver Fat Content

Abstract

Our objective was to determine how 8% weight loss influences subcutaneous, intra-abdominal, and liver fat (LFAT), as well as features of insulin resistance, in obese women with high versus low LFAT. A total of 23 women with previous gestational diabetes were divided into groups of high (9.4 ؎ 1.4%) and low (3.3 ؎ 0.4%) LFAT based on their median LFAT (5%) measured with proton spectroscopy. Both groups were similar with respect to age, BMI, and intra-abdominal and subcutaneous fat. Before weight loss, women with high LFAT had higher fasting serum insulin and triglyceride concentrations than women with low LFAT. At baseline, LFAT correlated with the percent of fat (r ‫؍‬ 0.44, P < 0.05) and saturated fat (r ‫؍‬ 0.45, P < 0.05) of total caloric intake but not intra-abdominal or subcutaneous fat or fasting serum free fatty acids. Weight loss was similar between the groups (high LFAT ؊7.4 ؎ 0.2 vs. low LFAT ؊7.7 ؎ 0.3 kg). LFAT decreased from 9.4 ؎ 1.4 to 4.8 ؎ 0.7% (P < 0.001) in women with high LFAT and from 3.3 ؎ 0.4 to 2.0 ؎ 0.2% (P < 0.001) in women with low LFAT. The absolute decrease in LFAT was significantly higher in women with high than low LFAT (؊4.6 ؎ 1.0 vs. ؊1.3 ؎ 0.3%, P < 0.005). The decrease in LFAT was closely correlated with baseline LFAT (r ‫؍‬ ؊0.85, P < 0.001) but not with changes in the volumes of intra-abdominal or subcutaneous fat depots, which decreased similarly in both groups. LFAT appears to be related to the amount of fat in the diet rather than the size of endogenous fat depots in obese women. Women with initially high LFAT lost more LFAT by similar weight loss than those with low LFAT, although both groups lost similar amounts of subcutaneous and intraabdominal fat. These data suggest that LFAT is regulated by factors other than intra-abdominal and subcutaneous fat. Therefore, LFAT does not appear to simply reflect the size of endogenous fat stores.

Magnetic resonance imaging and spectroscopy for monitoring liver steatosis

“…Previous studies have demonstrated that moderate weight reduction (around 8% body weight) leads to a marked reduction of IHCL content in subjects with type 2 diabetes (12) and women with previous gestational diabetes (13). Petersen et al (12) found that a reduction in IHCL content was associated with a marked improvement in hepatic insulin sensitivity, as reflected by an increase of insulin suppression of glucose production to 93% Ϯ 5% during a hyperinsulinemic clamp compared with 29% Ϯ 22% before the weight loss (P ϭ 0.04).…”

“…Results of MRS have shown to correlate closely with biochemical and histological assessments of liver triglyceride content (9,10), and to demonstrate a decrease in liver fat content following rosiglitazone therapy (11) or weight reduction (12,13). Other imaging modalities, such as ultrasonography and computed to-mography (CT), provide limited quantitative assessment (14,15).…”

A modified Mediterranean diet is associated with the greatest reduction in alanine aminotransferase levels in obese type 2 diabetes patients: results of a quasi-randomised controlled trial

“…Another limitation is the use of ALT as a biomarker of liver fat, which is only moderately correlated with liver fat content (correlation coefficients ranging from 0.4 [17] to 0.6 [18]) and not a more direct measure of liver fat such as that obtained from proton magnetic resonance spectroscopy.…”

Fish oil prevents sucrose-induced fatty liver but exacerbates high-safflower oil-induced fatty liver in ddy mice

“…With respect to HF dietinduced fatty liver, patients with fatty liver have been shown to consume significantly more saturated fat per day than control subjects matched for body mass index. 33 The amount of hepatic fat appears to be related to the amount of fat in the diet rather than to endogenous fat deposits in obese women, 34 suggesting that increased postprandial TG may favor fatty liver formation. In the current study, saturated fat-rich butter favored fatty liver formation more than did safflower oil, with greater postprandial TG concentration ( Table 5).…”