Meena Shah

High-Fat and High-Carbohydrate Diets and Energy Balance

The current American Diabetes Association guidelines for nutrition recommend a moderate increase in monounsaturated fats and a reduced intake of carbohydrate in patients with diabetes in whom high-carbohydrate diets deteriorate glycemic control and lipoprotein levels. High-fat diets, however, are believed to promote obesity, and some investigators may have reservations recommending such diets. This review thus investigates the role of diet composition in promoting obesity or achieving weight loss and its implications in patients with diabetes. Epidemiological studies show some evidence that fat intake is more importantly related to body weight than carbohydrate intake, but conclusions are weak because confounding variables, such as physical activity, smoking, and energy intake, were generally not controlled for. Metabolic studies under isoenergic conditions report no change in energy balance when fat intake is increased, but report a negative fat balance with substantial increase carbohydrate intake. During overfeeding, excess fat intake is stored as fat, whereas excess carbohydrate is mostly oxidized in the short term but can lead to substantial gain in fat stores because of reduced fat oxidation and considerable de novo lipogenesis in the long term. Spontaneous energy intake, however, is higher on an unrestricted high-fat diet compared with a high-carbohydrate diet, but the long-term effects are not known. Weight-loss intervention studies show that a hypocaloric high-carbohydrate diet is not associated with more weight loss than a high-fat hypocaloric diet. In conclusion, a high-monounsaturated fat diet to control glycemic control and lipoprotein levels in patients with diabetes should not affect weight loss or maintenance, provided that energy intake is carefully controlled.

High-volume exercise program in obese bariatric surgery patients: a randomized, controlled trial.

Weight regain is a problem among many bariatric surgery patients. Whether a high‐volume exercise program (HVEP), a strategy to limit weight regain, is feasible in these patients is unknown. The feasibility of an HVEP in obese post‐bariatric‐surgery patients was determined by randomizing 33 Roux‐en‐Y gastric bypass (RYGB) and gastric banding (GB) surgery patients with a mean BMI of 41 ± 6 kg/m2 to an HVEP or control group for 12 weeks. The HVEP group was instructed to expend ≥2,000 kcal/week in moderate‐intensity exercise. All patients were counseled to limit energy intake. Treatment effect was assessed by repeated measures analysis. During the last 4 weeks of the study, 53% of the HVEP group expended ≥2,000 kcal/week and 82% expended ≥1,500 kcal/week. Step count, reported time spent and energy expended during moderate physical activity, maximal oxygen consumption relative to weight, and incremental area under the postprandial blood glucose curve were significantly improved over 12 weeks in the HVEP group compared to controls (group‐by‐week effect: P = 0.009–0.03). Both groups reported significant improvement in some quality‐of‐life scales. Changes in weight, energy and macronutrient intake, resting energy expenditure (REE), fasting lipids and glucose, and fasting and postprandial insulin concentrations were not different between the two groups. HVEP is feasible in about 50% of the patients and enhances physical fitness and reduces postprandial blood glucose in bariatric surgery patients.

The role of diet, exercise and smoking in dyslipidaemia in HIV-infected patients with lipodystrophy

Lipodystrophy in HIV‐infected (LDHIV) patients receiving protease inhibitors (PIs) is associated with dyslipidaemia. Whether lifestyle factors play a role in dyslipidaemia in LDHIV subjects on PIs is not well characterized.

Nutrient and food intake in obese women on a low-fat or low-calorie diet

The low-fat group consumed significantly fewer calories from fat and more calories from carbohydrate at both 6 and 12 months than the low-calorie group, but their fat intake was still about twice their goal at both 6 months (39 gm per day) and 12 months (46 gm per day). The low-calorie group achieved their fat goal of 30% of calorie intake, but they consumed from 300 to 700 kcal more than their calorie goal. Caloric intake, physical activity, palatability, satiety, quality of life, and weight loss were not significantly different by treatment. Two studies, which gave patients hypocaloric diets of varying fat and carbohydrate content (fat calories 10% to 45%) for from 10 to 12 weeks, found no effect of diet composition on weight loss. In addition, one study, which gave patients a low-fat, energy-unrestricted diet (fat calories 19%), reported a weight loss of 10.1 lb at 16 to 20 weeks and 5.7 lb at 9 to 12 months, which is similar to that seen in the low-fat group in the this study. Most of the decrease in fat intake (90%) in the low-fat group resulted from a reduction in intake of fat from fat and oils; meat, fish, and poultry; dairy products; and sweets. The dietary changes in the low-fat group are consistent with those found in one study, which prescribed a 15% fat calorie diet to women with breast cancer. Intake of vitamin C increased in the low-fat group and decreased in the low-calorie group. This difference was significant and was caused by an increased intake of fruits and vegetables in the low-fat group and a decreased consumption of fruits in the low-calorie group. Calcium intake decreased significantly more in the low-calorie group because of a decreased intake of dairy foods.

Slower Eating Speed Lowers Energy Intake in Normal-Weight but not Overweight/Obese Subjects

BACKGROUND The effect of eating speed on energy intake by weight status is unclear. OBJECTIVE To examine whether the effect of eating speed on energy intake is the same in normal-weight and overweight/obese subjects. DESIGN The effect of slow and fast eating speed on meal energy intake was assessed in a randomized crossover design. PARTICIPANTS/SETTING Thirty-five normal-weight (aged 33.3±12.5 years; 14 women and 21 men) subjects and 35 overweight/obese (44.1±13.0 years; 22 women and 13 men) subjects were studied on 2 days during lunch in a metabolic kitchen. INTERVENTION The subjects consumed the same meal, ad libitum, but at different speeds during the two eating conditions. The weight and energy content of the food consumed was assessed. Perceived hunger and fullness were assessed at specific times using visual analog scales. STATISTICAL ANALYSES Effect of eating speed on ad libitum energy intake, eating rate (energy intake/meal duration), energy density (energy intake per gram of food and water consumed), and satiety were assessed by mixed-model repeated measures analysis. RESULTS Meal energy intake was significantly lower in the normal-weight (804.5±438.9 vs 892.6±330.2 kcal; P=0.04) but not the overweight/obese (667.3±304.1 vs 724.8±355.5 kcal; P=0.18) subjects during the slow vs the fast eating condition. Both groups had lower meal energy density (P=0.005 and P=0.001, respectively) and eating rate (P<0.0001 in both groups) during the slow vs the fast eating condition. Both groups reported less hunger (P=0.01 and P=0.03, respectively), and the normal-weight subjects reported more fullness (P=0.02) at 60 minutes after the meal began during the slow compared with the fast eating condition. There was no eating speed by weight status interaction for any of the variables. CONCLUSIONS Eating slowly significantly lowered meal energy intake in the normal-weight but not in the overweight/obese group. It lowered eating rate and energy density in both groups. Eating slowly led to lower hunger ratings in both groups and increased fullness ratings in the normal-weight group at 60 minutes from when the meal began.

Menu Labels Displaying the Kilocalorie Content or the Exercise Equivalent: Effects on Energy Ordered and Consumed in Young Adults

Purpose. Determine the effect of menu labels displaying the energy content of food items or the exercise equivalent on energy ordered and consumed at lunch and energy intake for the remainder of the day in young adults. Design. Subjects were randomized to a menu with no labels (no-labels), menu with kilocalorie labels displaying the energy content of the food items (kcal-labels), or menu with exercise labels displaying the minutes of brisk walking needed to burn the food energy (exercise-labels). Setting. The study was conducted in one dining area located in a metabolic kitchen at the Texas Christian University and another located in a residence occupied by graduate students. Subjects. Of the 300 subjects, 55.7% were female, 77.3% were college students, 88% were white, and 88% were non-Hispanic. Mean body mass index and age were 24.2 ± 4.5 kg/m2 and 21.9 ± 2.3 years, respectively. Intervention. All menus contained the same food/beverage choices. Subjects ordered and consumed foods/beverages for lunch from the menu to which they were assigned. Subjects were blinded to study purpose. Measures. Energy ordered and consumed at lunch were assessed from the weight of the food ordered and consumed, respectively, and the energy content of the same foods available on the restaurant Web site. Postlunch energy intake was assessed by food recall. Analysis. Analysis of covariance, adjusted for premeal hunger levels and gender, determined the effect of menu type on energy ordered and consumed and postlunch energy intake. Results. Significant menu effect was observed for energy ordered (p = .008) and consumed (p = .04) at lunch. The exercise-labels group ordered significantly (p = .002) less energy (adjusted mean [confidence intervals]: 763 [703, 824] kcal) at lunch, compared to the no-labels group (902 [840, 963] kcal) but not compared to the kcal-labels group (827 [766, 888] kcal). The exercise-labels group also consumed significantly (p = .01) less energy (673 [620, 725] kcal) at lunch, compared to the no-labels group (770 (717, 823) kcal) but not compared to the kcal-labels group (722 [669, 776] kcal). Energy ordered and consumed were not different between kcal-labels and no-labels groups. There was no difference in postlunch energy intake by menu type. Conclusion. The menu with exercise-labels resulted in less energy ordered and consumed and this did not lead to greater energy consumption post lunch, compared to the menu with no-labels in young adults largely made up of normal-weight, non-Hispanic white college students.

Food serving size knowledge in African American women and the relationship with body mass index.

OBJECTIVE To examine serving size knowledge in African Americans and how it is related to body mass index (BMI). DESIGN Serving size knowledge of food commonly consumed by African Americans was assessed by asking the subjects to select the amount of food considered to be a single serving size by the United States Department of Agriculture and the Food and Drug Administration. Seventeen food items were tested, and the amounts selected were weighed. Body mass index was estimated from measured height and weight. SETTING Churches. PARTICIPANTS Ninety-five African American women. MAIN OUTCOME MEASURES Amount of food selected and BMI. ANALYSES The amount of food selected was compared with the respective standard serving using the 1-sample Wilcoxon signed rank test. The association between BMI and the amount selected was assessed by logistic regression. RESULTS The subjects significantly overestimated (P = .001 to .02) serving sizes for cornflakes, apple, watermelon, butter, whole milk, chips, and regular soda. Body mass index was significantly associated with overestimation of cornflakes, butter, cookies, and macaroni and cheese (P = .01 to .03), and the odds ratio for overestimating these food items was 1.46-1.65 times greater per 5-unit increase in BMI. CONCLUSIONS AND IMPLICATIONS African American women overestimated the serving sizes for 7 of the food items tested, and 4 of the estimates were correlated with BMI. Education regarding serving size is recommended for certain food items.

Effect of a High-Fiber Diet Compared With a Moderate-Fiber Diet on Calcium and Other Mineral Balances in Subjects With Type 2 Diabetes

OBJECTIVE High levels of dietary fiber, especially soluble fiber, are recommended to lower serum cholesterol levels and improve glycemic control in patients with type 2 diabetes. It is not clear, however, how high levels of fiber affect mineral balance. RESEARCH DESIGN AND METHODS In a randomized crossover study, 13 patients with type 2 diabetes were fed a high-fiber (50 g total and 25 g soluble fiber) and a moderate-fiber (24 g total and 8 g soluble fiber) diet of the same energy, macronutrient, calcium, magnesium, and phosphorus content for 6 weeks each. Intestinal calcium absorption was determined by fecal recovery of 47Ca. Stool weight and mineral content were assessed during 3 days, and 24-h urinary mineral content and serum chemistry were assessed over 5 days at the end of each phase. The results were compared by repeated-measures ANOVA. RESULTS Compared with the moderate-fiber diet, the high-fiber diet increased stool weight (165 ± 53 vs. 216 ± 63 g/day, P = 0.02) and reduced 24-h urinary calcium (3.3 ± 1.7 vs. 2.4 ± 1.2 mmol/day, P = 0.003) and phosphorus (29.2 ± 5.5 vs. 26.0 ± 3.2 mmol/day, P = 0.003) excretion and serum calcium concentration (2.33 ± 0.06 vs. 2.29 ± 0.07 mmol/l, P = 0.04). Calcium absorption, stool calcium, magnesium, and phosphorus content and serum phosphorus concentration were not significantly different with the two diets. CONCLUSIONS A high-fiber diet rich in soluble fiber has a small impact on calcium and phosphorus balance in subjects with type 2 diabetes. It may be prudent to ensure adequate intake of calcium and other minerals in individuals consuming a high-fiber diet.

Ingestion of High Molecular Weight Carbohydrate Enhances Subsequent Repeated Maximal Power: A Randomized Controlled Trial

Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW) carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW) carbohydrate ingestion. The effect of the HMW carbohydrate, however, on the performance of intense resistance exercise following prolonged-intense endurance training is unknown. Sixteen resistance trained men (23±3 years; 176.7±9.8 cm; 88.2±8.6 kg) participated in a double-blind, placebo-controlled, randomized 3-way crossover design comprising a muscle-glycogen depleting cycling exercise followed by ingestion of placebo (PLA), or 1.2 g•kg•bw-1 of LMW or HMW carbohydrate solution (10%) with blood sampling for 2-h post-ingestion. Thereafter, participants performed 5 sets of 10 maximal explosive repetitions of back squat (75% of 1RM). Compared to PLA, ingestion of HMW (4.9%, 90%CI 3.8%, 5.9%) and LMW (1.9%, 90%CI 0.8%, 3.0%) carbohydrate solutions substantially increased power output during resistance exercise, with the 3.1% (90% CI 4.3, 2.0%) almost certain additional gain in power after HMW-LMW ingestion attributed to higher movement velocity after force kinematic analysis (HMW-LMW 2.5%, 90%CI 1.4, 3.7%). Both carbohydrate solutions increased post-exercise plasma glucose, glucoregulatory and gut hormones compared to PLA, but differences between carbohydrates were unclear; thus, the underlying mechanism remains to be elucidated. Ingestion of a HMW carbohydrate following prolonged intense endurance exercise provides superior benefits to movement velocity and power output during subsequent repeated maximal explosive resistance exercise. This study was registered with clinicaltrials.gov (NCT02778373).

Comparison of nutrient intakes in South Asians with type 2 diabetes mellitus and controls living in the United States

AIMS Despite having a high risk for type 2 diabetes mellitus (T2DM), little is known about the relationship between nutrient intakes and T2DM in South Asians (SA) in the U.S. In addition, the available data are limited to a few macronutrients and collected using subjective measures. Therefore, we compared macro- and micro-nutrient intakes of SA migrants with and without T2DM using an objective measure. METHODS SA in the U.S. with T2DM (n = 44) and controls (n = 33) reported their dietary intake using image-assisted dietary assessment method. They took pictures of all foods/drinks consumed on two weekdays and one weekend day. Age, gender distribution, and body mass index were similar across the two groups. RESULTS SA with T2DM, as compared to controls, consumed less total energy (mean difference: 499 kcal/d; p < .0001), linoleic acid (3.6 g/d; p = .003), dietary fiber (8.6 g/d; p < .0001), vitamin A (262 µg/d; p = .003), vitamin E (2.7 mg/d; p = .007), calcium (133 mg/d; p = .01), magnesium (116 mg/d; p < .0001), zinc (1.4 mg/d; p = .004), potassium (754 mg/d; p < .0001), and β-carotene (1761 µg/d; p = .03). SA with T2DM, as compared to controls, were significantly more likely not to meet the requirements for linoleic acid, dietary fiber, vitamin E, calcium, magnesium, zinc, and potassium (p < .05). CONCLUSIONS SA with T2DM, compared to controls, consume less total energy and have lower consumption of many nutrients associated with reduced risk of T2DM. Dietary interventions to reduce risk for T2DM are warranted in SA.