Excessive calories from snacking increase liver fat

By Will Boggs MD

NEW YORK (Reuters Health) - Hypercaloric diets with increased meal frequency are associated with increases in intrahepatic triglycerides (IHTG), researchers from The Netherlands report.

"I hope that in the battle against obesity and in the prevention of obesity, additional attention will be given to eating pattern besides to caloric content and macronutrient composition," Dr. Mireille J. Serlie from Academic Medical Center Amsterdam told Reuters Health by email. "Also, professionals should be aware that the metabolic handling of nutrients might be different depending on meal timing."

High-fat diets increase IHTG in lean and obese humans, but whether the frequency and timing of food intake influences IHTG remains unclear.

Dr. Serlie and colleagues studied the effects of increasing meal frequency or meal size in a six-week study of 37 lean, Caucasian men who were randomized to one of four hypercaloric diet groups or a control group.

The groups included: high-fat-high-sugar diet (HFHS) divided into three meals daily (HFHS-size); HFHS divided into three meals daily with a snack consumed 2-3 hours after each meal (HFHS-frequency); high-sugar diet (HS) divided into three meals daily (HS-size); and HS divided into three meals daily with a snack consumed 2-3 hours after each meal (HS-frequency). All but the control group received a 40% caloric surplus over the ad libitum weight-maintaining diet.

Body mass index (BMI), IHTG, and insulin sensitivity did not change in the control group, according to the May 6 Hepatology online report.

Subjects in the four treatment groups gained an average of 2.5 kg during the six-week study.

IHTG increased significantly in both HFHS- and HS-frequency groups, whereas the HFHS- and HS-size groups experienced no change in IHTG. The IHTG increase tended to be highest in the HS-frequency group.

Total abdominal fat increased according to the same pattern, whereas fasting glucose and insulin sensitivity did not change with these dietary interventions.

Plasma leptin levels increased in all four dietary intervention groups, but glucoregulatory hormones did not change.

When the size groups were pooled and the frequency groups were pooled, only the frequency groups showed significantly increased IHTG and abdominal fat.

"This suggests that when people eat more than needed and thus increase their body weight, a snacking eating pattern contributes independently to an unfavorable storage of fat with possible metabolic and medical consequences in the longer term," Dr. Serlie said. "But we cannot draw any conclusions on the same eating pattern in a eucaloric setting and thus stable weight condition."

"More long-term studies are needed including females and older subjects," Dr. Serlie said. "It would also be interesting to study whether eating pattern has the same effect on liver and abdominal fat in children at risk for obesity."

Dr. Claudia PMS de Oliveira from University of Sao Paulo School of Medicine in Brazil, who has several published studies in nonalcoholic fatty liver disease, told Reuters Health via email, "I think that physicians should continue recommending healthy meals and understand that there are some limitations in this study." She specifically mentioned the small sample size and the use of high fructose and fat in the diets.

She added, "We need randomized trials to prove this conception, however, I believe that a low carbohydrate diet, mainly low fructose and the use of whole-carbohydrates enriched with high-fiber, is a better meal for reducing the induction of carbohydrate responsive transcription factors like CHREBP or insulin-mediated induction of SREBP1c, PPAR gamma or LXR."

SOURCE: http://bit.ly/1gIqjkv

Hepatology 2014.