Liver, an important organ in the human body, is not much talked about despite its versatility in fighting against infections, aiding in digestion, storing energy and cleaning the blood. This organ residing in each of us contains a designated amount of fat which is normal but the problem arises when more than 5-10% of the liver’s weight is fat resulting in what is termed as a fatty liver. Non-alcoholic fatty liver disease (NAFLD) is the build-up of excess fat in the liver cells that’s not a result of alcohol commonly seen in overweight or obese people. NAFLD can be split into four stages that includes simple fatty liver (steatosis), non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis (here, the individual is at risk for hepatocellular carcinoma (HCC)). Many people get into the first stage even before realising what’s happening but it can take years together to reach the 3rd or 4th stage before which significant lifestyle changes can prevent this condition from worsening. Otherwise, such high fat accumulation in the liver paves way for other serious health conditions such as diabetes (this once again increases the risk of heart disease), high BP and kidney disease.
Prevalent rates of the disease are different in different parts of the world with maximum prevalence of 20-30% recorded in Western countries. Earlier days saw the need for humans to hunt or gather food for fulfilling nutrient requirements and this included energy expenditure to replenish the lost energy with food. But now, despite the prevalence of malnutrition and poverty among a class of people there are a majority of individuals who are provided with a surplus of daily calories thereby increasing the rates of obesity and overweight worldwide. This kind of an obesity epidemic has made it possible for diseases such as NAFLD to become diagnosis of chronic liver disease. Though it can affect any individual of any age it is generally the middle-age people who are affected. Though there are different treatment plans proposed for NAFLD weight loss and lifestyle management exist as the most reliable forms of treatment plans till date. We have research supporting the fact that lifestyle interventions reduce markers of liver lipid and metabolic control along with reducing intrahepatic lipid (IHL) and studies even show that increased exercise practices are linked to lower levels of IHL but it is also essential to remember that weight loss is difficult to achieve and even more difficult to maintain. Even The American Gastroenterological Association, the American Association for the Study of Liver Diseases, and American College of Gastroenterology all of them recommend physical activity as one of the best treatment methods for NAFLD. Given below is a detailed study of hbow exercise affects NAFLD.
Aerobic Exercise As a Tool Against NAFLD
A non-randomized clinical trial segregated 90 NAFLD patients into two groups-case and control groups. Height, weight and BMI calculations were made on each participant. Liver enzymes (AST, ALT, ALP), fasting blood sugar (FBS) and lipid profile (TG, total cholesterol and HDL cholesterol) were measured. In the case group, when TG levels were above 400 mg/dl enzymatic method was used for calculating LDL cholesterol and in the control group, medical therapy with 1000 mg vitamin C and 400 units vitamin E were prescribed. Besides medical therapy (just like the control group) 30 minutes of aerobic exercise with maximal heart rate thrice a week for around 3 months was performed in the case group.
Of the 90 participants 57 of them were men and 33 were women. In the case group, 29 were men and 16 were women while in the control group 28 were men and 17 were women and all of them were between 17 and 56 years of age. Once both groups were done with their stipulated duration of aerobic exercise performance serum levels of enzymes and liver echogenicity in individuals with NAFLD was decreased. It was observed that in the case group, 35 patients were in stage 1, 4 and 6 patients were in stage 2 without sonographic fatty liver. In the control group, 33 patients were in stage 1, 9 patients were in stage 2 and the fatty liver of 3 patients was resolved by sonography. Weight, BMI FBS, TG, HDL, AST, ALT and VFM values varied significantly before and after the trial in the case group. In the control group there was significant difference found in weight, BMI, SBP, DBP, TG and LBM values before and after trial.
Effect of Resistance Training on NAFLD
21 NAFLD patients leading a sedentary lifestyle were involved in the study and each of them were randomly assigned to either the exercise (11 participants) or standard care (10 participants) group respectively. Physical examination, full medical history and fat measures (both subcutaneous and visceral) were done on each of the individuals. The exercise group performed resistance exercises on non-consecutive days for a period of 8 weeks for around 45-60 minutes daily with 10 minutes of warm-up session before the exercise. The programme involved eight exercises and the participants were encouraged to increase resistance used every week when possible.
While 2 participants were removed in between the research quoting various reasons the other 19 participants completed the study. Results showed that BMI remained unchanged in both the groups during the study with insignificant changes seen in weight, waist or hip circumference, waist to hip ratio, body composition and visceral or subcutaneous fat in either group.
There was a 13% reduction in IHL values witnessed in the exercise group on performance of resistance training with no changes seen in the control group. Three participants in the exercise group witnessed great improvements moving over from having significant NAFLD to staying within normal limits whereas none of the control subjects moved into the normal liver fat range. The exercise group also showed improved glucose control and significant improvement in insulin sensitivity. Fasting glucose levels also reduced in the exercise group after intervention compared to the control group. The study is a clear example that resistance exercises reduced IHL, increased insulin sensitivity and improved metabolic flexibility in NAFLD patients independent of weight loss.
Evidences in Favour Of & Against Exercises
End-stage liver disease (ESLD) and HCC are the final outcomes of fatty liver disease and we don’t have studies until now showing the effects of exercise on them. But logically, when individuals recover from NASH the risk of going into any of the other stages is minimal. A randomized control study by Eckard et al. focusing on lifestyle interventions that included daily physical activity showed significant reduction of NASH score. Another RCT on 31 NASH patients showed that 48 weeks of intense intervention pave way for a 2.4-point reduction of score.
A 2012 meta-analysis done by Keating et al. on 439 subjects showed only a small reduction in liver fat content. A systematic review by Golabi et al. on 8 randomized trials on 433 individuals showed a 30.2% reduction in hepatic fat that was a result of regular exercising and a 49.8% reduction in liver fat that’s a result of a combination of both exercise and dietary intervention.
There are a couple of studies that focused on the modality, intensity and duration of exercise that had a definite impact on NASH patients. An analysis of 813 NAFLD patients who were asked to self-report on their physical activity status came to the conclusion only those patients who performed vigorous physical activity were at a decreased risk of entering the NASH stage and those patients who doubled the exercise intensity decreased their risk of advanced fibrosis even further. Another study in Japan focusing on five cycles of HIIT training followed by 3-min recovery periods showed an optimal reduction in liver fat. Another study segregated 48 patients randomly into four different groups-low-intensity/high-volume, high-intensity/low-volume, low-intensity/low-volume and no exercise. While each group did experience a significant reduction in liver fat there was not much difference witnessed between the regimens. This shows that aerobic exercise done even at low-intensity reduces fat content of the liver. Another study by Bacchi et al. compared the effects of aerobic versus resistance training on 31 NASH patients over a 4-month period. While liver fat content did reduce there was no difference in results seen between the two exercise forms. A randomized trial on 196 subjects showed that aerobic exercise resulted in a greater reduction in hepatic fat content than resistance training program. But all these studies had one ideology in common-hepatic fat content decreased even when there as no change in weight loss observed in different studies. This clearly shows that physical activity and exercise have a direct impact on the liver.
The Effect of Physical Exercise on Fatty Liver Disease: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5954622/
The Effect of an Aerobic Exercise on Serum Level of Liver Enzymes & Liver Echogenicity in Patients with Non-alcoholic Fatty Liver Disease: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4017540/
Resistance Exercises Reduces Liver Fat & its Mediators in non-alcoholic Fatty Liver Disease Independent of Weight Loss: https://gut.bmj.com/content/60/9/1278
Our moms and grandmas are leading longer lives than expected seeing their grandkids and great grandkids attend school and college! They belong to a generation who is blessed to witness such a sight in their life and all this is because of advancements in science, especially in the field of health care. Life expectancy of the elderly generation is reaching new highs and so are their obesity rates. That’s because, ageing is accompanied by changes in body composition of individuals. Above the age of 70, both fat free mass and fat mass decrease with fat mass being redistributed in the visceral component and fat deposits are significantly visible in the skeletal muscle and liver. Body fat is mainly determined by the difference between energy intake and energy expenditure. Though there is no great increase in intake portion sizes in the elderly population their physical activity levels also witness a downslide and such decreased energy expenditure plays a prominent role in increasing fat mass with ageing. Also, there is a 2-3% decrease in resting metabolic rate every decade after the age of 20 and all these together account for decrease in energy expenditure with ageing.
But the actual question is whether obese elderly individuals must try to lose weight! For some of you who wonder what’s the point in asking questions when one is obese and there are clear evidences that obesity is a serious risk factor for heart diseases, diabetes, hypertension and hyperlipidaemia, I guess you have not heard of the obesity paradox! According to it, certain studies and meta-analyses show that a higher BMI can be protective of the elderly population decreasing (instead of increasing) their risk of death. There are various population-based studies that show that weight loss is linked to an increase in mortality rates; weight loss increases muscle loss (sarcopenia), there is a loss of the protective effect of fat (such as against hip fractures) and fat loss also exists which releases fat-soluble toxins into circulation. The next question is whether BMI is a good measure of body fat? In fact, it is not! People sometimes tend to lose height due to bending of the spinal cord as they age and, in such cases, some of them seem to have a higher BMI when their weight has not changed at all. Also, muscle loss, fat distribution and fat increase are not evident in BMI values. In such cases, waist circumference (WC) acts as a perfect measure for calculating obesity in older adults as this gives a clear picture of total fat and intra-abdominal fat. WC is extremely cost-effective, useful and can give a clear picture of the visceral fat adiposity levels in an individual. WC is one of the five criteria that defines metabolic syndrome which is in the first place linked to functional decline, frailty and disability. While ageing itself brings about disability, functional decline and loss of mobility studies show an association between BMI and mobility impairment. But there are very few which focus on WC as a factor for functional decline, falls and decrease in quality of life. Osteoarthritis (OA) is yet another reason for diminishing functional abilities in the elderly population and it also has the ability to increase changes in body composition that occur with aging. A study specifically focused on a cohort of older adults at risk for OA probing whether increased WC impacted quality of life, physical activity and daily life activities in these people.
Osteoarthritis Initiative (OAI)
Osteoarthritis initiative (OAI) is an observational study of osteoarthritis in adults aged between 45 and 79 years belonging to any ethnic group. Those suffering from rheumatoid arthritis, severe joint space narrowing, bilateral total knee replacements, unable to undergo an MRI, unable to provide blood samples or having any comorbidities were excluded from participating in the study. Baseline information in the form of questionnaires, interviews and physical assessment were collected. Every participant went through follow-up assessments annually and the present study used six-year outcome data for analysis.
All the study participants were put into one of the three subgroups-clinically significant knee osteoarthritis at risk of disease progression, subjects at high risk of developing clinically significant knee OA (incident) and control group. Individuals in the progression subgroup complained frequently of knee symptoms or radiographic tibiofemoral knee OA in at least one native knee. Though the incident subgroup did not have baseline symptomatic knee OA they had certain other risk factors such as the presence of heberden’s nodes in both hands, increased weight, previous knee injury or operation, family history and pain in the knee on most days of the preceding month. The control group neither had pain nor risk factors or radiographic findings.
The study consisted of 2,182 subjects whose height, weight and waist circumference were measured. Waist circumference was measured at the level of the umbilicus between the lower rib and the iliac crest. BMI was calculated as weight divided by height squared. Gait was calculated using the 20m walk test using which each of the participant’s walking speed was noted down. The study also measured occupational, household and leisure activities using the physical activity scale for the elderly (PASE) which is a 26-item questionnaire with greater scores indicating higher intensity of activity.
Results showed that there was a higher proportion of women in the lower WC quartile and the number of medications increased with increasing WC quartile. Also, the proportion of individuals with knee OA increased by quartile. The study compared individuals who participated in the research to those who were excluded and found that the excluded individuals were older, less likely to belong to the female sex and were likelier to have higher comorbidities score and medications. They also had lower SF-12 (quality of life score) score at baseline but there were no differences found in PASE scores. The outcomes were measured at baseline and six years after start of study-it was found that SF-12 rates dropped as waist circumference increased at baseline and follow-up. A decline in PASE score was also observed over time and also between groups at baseline and 6 years after follow-up. Late-life disability index (LLDI) scores decreased at follow-up and activities of daily living (ADL) impairments increased significantly from 18% in the lowest WC quartile to 36.6% in the upper WC quartile.
SF-12 values were observed to be age-dependent and those in the high WC quartile had lower scores than the lowest quartile. High WC quartile subjects had decline in PASE score compared to other categories but this was evident only in the 70+ age group. LLDI score also had maximum impact in the same age group compared to the low WC quartile. Also, gait speed was lowest in the highest WC quartile compared to other categories. Patients with OA had lower outcome measures compared to the low WC quartile. The study is a clear indication that high waist circumference is linked to decreased quality of life and physical activity. Hence, rather than focusing on BMI the primary focus must be to improve functional stability, manage weight and increase physical fitness in such a way that there is an overall improvement in physical performance and quality of life of the elderly individual.
The Impact of Waist Circumference on Functional and Physical Activity in Older Adults: Longitudinal Observational Data from the Osteoarthritis Initiative: https://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-13-81
Obesity in the Elderly: More Complicated than You Think: https://www.mdedge.com/ccjm/article/96020/geriatrics/obesity-elderly-more-complicated-you-think/page/0/1
Obesity in the Elderly: https://www.ncbi.nlm.nih.gov/books/NBK532533/
It’s not surprising when many individuals enroll for a gym membership or a weight loss program with the only aim of losing tummy weight. You might be slim and trim but there might be a small tummy protruding out of your Western outfit that screams for immediate attention. Some people accumulate fat around their thighs, some around their hands and hips but a majority of the individuals suffer from fat accumulation around their tummies (men are primary victims here). Worldwide, obesity and overweight have catapulted the lives of many and according to WHO, obesity is the accumulation of excess body fat that might impair health. Obesity rates have doubled since the 1980s becoming one of the primary reasons for the widespread prevalence of metabolic disturbance owing to increased intake of processed foods that are overloaded with sugar and unhealthy fats. Such excess fat accumulation have debilitating effects on the body’s health increasing levels of bad (LDL) cholesterol, lowering good (HDL) cholesterol levels, hinders body’s response to insulin thereby increasing blood sugar levels and prevails as the major risk factor for numerous diseases including heart attacks, strokes, high blood pressure, cancer, diabetes and even depression.
Any type of fat is bad and overweight is not appreciated but when it comes to health there is more concern placed on how much abdominal fat you have and not on how much you weigh. Though BMI exists as the commonly used measure for determining a person’s health this is not an exact measure as BMI only calculates total body fat without regarding how the fat is distributed. So, why does abdominal fat hold more importance than total body fat in determining a person’s health? Though we don’t have exact reasons scientists are indeed coming up with numerous convincing reasons for the same.
Abdominal obesity (AO) is excess fat stored in two different abdominal regions-subcutaneous and visceral. Subcutaneous adipose tissue (SAT)is located in fatty tissues just beneath the skin acting like fat that’s present everywhere else in the body. This is neither too harmful nor helpful. Visceral adipose tissue (VAT) is that fat which is located around the internal body organs that exists as the primary health hazard. Such visceral obesity was linked with the overactivity of the body’s stress response mechanisms that raise blood pressure, blood sugar levels and heart risk.
So, if BMI is not right maybe an MRI or CT would help us in measuring the amount of visceral fat. But not everyone can afford this right? One of the simpler methods is to measure the waist-to-hip ratio-a ratio measure above 0.95 in men raises the risk of heart attack or stroke while in women it is 0.85. But, much more convenient is the waist circumference (WC) that includes only one and not two measures. In today’s junk food world, there are a number of factors that contribute towards pronounced WC and VAT stores including sedentary lifestyle behaviours, absence from exercise routines and consumption of fatty and sugar-enriched foods. Research shows that VAT increases by more than 200% in men and almost 400% in women between the ages of 25 and 65. Besides food habits, smoking, alcohol consumption, age and hormones increase the risk of abdominal obesity. It has also been observed that VAT levels increase during pregnancy and menopause starting right from perimenopause and going up to the end of menopause.
Getting Rid of Abdominal Fat: A Click Away?
It is common these days to see ads and social media marketing platforms trying to lure clients by coming up with newer ideas and weight loss gimmicks including the ones such as: the secret pill for belly fat reduction or “Dissolve belly fat within 10 days by drinking this daily!” This makes it even more difficult for health and nutrition experts qualified in diet and nutrition counselling to come up with better solutions that are practical yet effective to help people stop from falling a prey to such gimmicks and take up the best solution to correct abdominal obesity. The right approach is to follow a healthy diet by creating recommended calorie deficits suitable for the individual’s body type and practicing daily exercises. The point now is whether there are specific dietary approaches, nutrients suggested or foods recommended to fight abdominal obesity. Given below are some of the studies that have dealt dealing with abdominal obesity with dietary and exercise measures.
Meta-analysis & Review of Randomized Control Trials
Though we have studies showing the effect of exercise on abdominal fat there are not many reviews that deal with lifestyle interventions for AO. Databases such as Medline and Embase were searched thoroughly for randomized control trials (RCTs). A 12-month data was used for the study independent of the length of the intervention. Though the search came back with more than 2900 records, there were 15 trials selected for analysis based on different restriction criteria. All except 3 were lifestyle interventions that proposed diet and physical activity changes. Each of the study included anywhere between 34 and 439 participants and the studies were conducted between three months and three years.
Results showed that participants in a behavioural change program reduced WC by -1.88 cm and those in a combined program lost a mean of -4.11 cm. Meta-regression analysis showed a mean difference of -2.39 cm between both types of programs showing that a combined approach is the best way possible. Three studies focusing on gender observed that male participants lost a mean of -2.61 cm WC and female participants reduced their WC by -1.63 cm. Of the six studies that practised combined intervention, four chose a physical activity (PA) component, one a very low-calorie diet and another one tested diet and PA separately as well as combined with the combination giving the best result.
Effect of Diet on Postmenopausal Women
The study here focused whether exercise in combination with diet restriction reduced abdominal fat to a greater extent that one triggered by diet alone. This study is a secondary analysis of the SHAPE-2 study (SHAPE was the Sex Hormone and Physical Exercise study designed to find out the effect of weight loss with/without exercise on biomarkers of postmenopausal breast cancer risk) in which 243 healthy overweight or obese postmenopausal women participated. Eligibility criteria included postmenopausal women, having a BMI between 25 and 35, insufficiently physically active and not diagnosed with diabetes or cancer. There was a 4-6 week run-in period at the start of the study in which a personalized standardized diet that conformed to the Dutch National Guidelines for a Healthy diet (50-60% carbohydrates, 15-20% protein, 20-35% fat, a max of 1 alcoholic drink daily, >25g of fibres per day, 200g of vegetables and 2 servings of fruits) was prescribed. The run-in period was mainly designed to find out the macronutrient intake among participants and stabilize body weight. Study participants were split into one of the three groups: diet group (97 participants), exercise plus diet group (98 participants) and control group (48 participants) respectively. The intervention programs were designed with an aim of reducing 5-6 kg of body weight in 10-14 weeks’ time. Dietitians and physiotherapists monitored the participants’ weight loss performance and self-weighing was performed. When weight loss did not meet or exceed 0.5 kg/week in participants for 3 consecutive weeks there was extra attention given to these participants to change their diet or exercise routine. After weight loss goal was achieved, a weight maintenance (2-6 weeks) was started that included balancing between intake and expenditure levels.
Participants in the diet group were given a diet with a calorie restriction of 3500 kcal/week and asked to maintain their regular physical activity. Participants in the exercise plus diet group followed a 4h/week exercise program (this included an energy expenditure of 2530 kcal/week). The exercise program included two 60-min group sessions of combined strength and endurance training conducted by physiotherapists and two 60-min Nordic walking session per week. This exercise intervention was combined with a small caloric intake restriction of 1750 kcal/week to enable 5-6 kg weight loss in a short time. All participants were regularly monitored by phone calls from dietitians.
Abdominal fat measurements (subcutaneous abdominal adipose tissue (SAAT) and intra-abdominal adipose tissue [IAAT]) were taken at baseline and after 16 weeks. SAAT and IAAT were summed together to obtain total abdominal adipose tissue (TAAT) measurements. Total body fat, lean mass, height and body weight measurements were also taken. At the end, 92 women in the diet group, 94 in the exercise plus diet group and 45 in the control group completed the study. Almost 70% of women at least attended four diet-group sessions and 81% attended the group exercise session. Participants in the diet group lost -4.9 kg and -5.5 kg in the exercise plus diet group. There was a -2.8% and -4.4% decrease in body fat percentage with diet and exercise plus diet group respectively. Exercise plus diet group lost more body fat percentage compared to other groups.
Compared to the control group, TAAT, SAAT and IAAT decreased significantly in both intervention groups. TAAT and SAAT decrease was significantly larger in the exercise plus diet group compared to the diet group-a difference of -15 cm2 for TAAT and -11 cm2 for SAAT. There was slightly more decrease seen in IAAT measurements in the exercise plus diet group than in the diet group compared to control.
The study found a 6-7% weight loss in healthy and overweight-to-obese postmenopausal women that led to a reduction in both intra-abdominal and abdominal subcutaneous fat. Weight loss that occurs as a combination of both exercise and calorie restriction paved way for enhanced changes in subcutaneous abdominal fat but with no changes in intra-abdominal fat when compared to weight loss induced by calorie restriction only.
Recent Trends in Managing Abdominal Obesity
Intermittent Fasting (IF): Though there is no standard protocol followed for intermittent fasting the general approach includes some level of fasting or energy restriction for 1-3 days/week with or without restriction on the remaining days. But a systemic review of 12 studies comparing IF with continuous energy restriction diets showed that all diet patterns resulted in similar weight loss and reduction in waist circumference irrespective of fasting or energy intake timings followed.
High Protein Diet: Proteins have always been considered as a friend of weight loss as it gives enhanced satiety and resting energy expenditure. But there are no convincing evidences from studies showing that a higher protein diet reduces abdominal obesity compared to other energy-restricted diets.
Palaeolithic-style Diet: This diet trend tries to mimic the eating habits of our early Palaeolithic age ancestors that includes elimination of certain food groups and foods not available during the Palaeolithic era. There are very few studies that focus on this diet as a means to reduce abdominal obesity and the information from them are also not convincing to say that a Paleo-style diet is a good target to curb abdominal obesity.
Green Tea: Green tea has been sought after for its benefits in effective weight loss including reducing abdominal obesity. Green tea catechins (GTC) have been said to have a synergising effect on energy expenditure, fat absorption and fat oxidation. Although GTC show advantages in animal studies the dose needed for creating significant difference in WC in humans display unrealistically high quantities.
DASH & Mediterranean Diets: The NIH-developed Dietary Approach to Stop Hypertension (DASH) diet and the Mediterranean diet were selected as the “2018 Best Overall Diets” as both of them are great options to encourage individuals to incorporate them in their daily lives for weight loss benefits. The DASH diet promotes weight loss and reduces risk of heart disease while the Mediterranean diet leads to lower cardiometabolic disease rates.
There is no one specific magic diet, food or ingredient that can promote weight loss, especially abdominal obesity reduction. It is always better to eat a healthy diet and perform regular physical activity to lose weight and stay healthy. Don’t get swayed away by misleading information about the latest trends for belly fat. It is always better to get in touch with registered dietitian nutritionists to get yourself going with the best diet plan that suits you instead of going behind those that eliminate food groups or promote fasting as a means to lose weight.
Therapeutic Treatment for Abdominal Obesity in Adults: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6121087/
Effect of Diet With or Without Exercise on Abdominal Fat in Postmenopausal Women- A Randomized Trial: https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-019-6510-1
Targeting Abdominal Obesity Through the Diet: https://journals.lww.com/acsm-healthfitness/Fulltext/2018/09000/TARGETING_ABDOMINAL_OBESITY_THROUGH_THE_DIET__What.8.aspx?WT.mc_id=HPxADx20100319xMP
We live in a period in which overweight/obesity rates are overpowering normal body weight in kids and adults equally. While dietary factors hold primary responsibility its also our sedentary lifestyle and physical inactivity that play an equal role in triggering excess body weight in kids, adolescents and even toddlers. This excess body weight now exists as one of the biggest medical problems around the world affecting people from all walks of life disrupting their quality of living. Some of the major long-term issues include diabetes mellitus, dyslipidemia, hypertension, sleep apnea, musculoskeletal problems, gastrointestinal disease and psychosocial difficulties. Overweight/obese kids (above the age of 7) have maximum risk of growing into obese adults with increased risk of cardiovascular disease. Even the World Health Organization (WHO) shows that overweight and obesity exist as the leading cause of premature death worldwide and as a serious risk factor for mortality during adulthood too.
Obesity is nothing but body weight ranges well above the defined limits which leads to higher body mass index values and waist circumference. Statistics show that obesity rates in America have more than doubled in the past few decades and the results are almost similar elsewhere too - India is becoming one of the top countries with maximum childhood and adult obesity rates, the incidence of obesity and overweight in the Iranian population is 10.1% and 4.79% respectively and Brazil has experienced a drastic nutritional transition from decrease in malnutrition to increase in obesity/overweight rates. Though genetics and environmental factors do play an integral role in determining obesity risk in kids most researches also show that macronutrient composition of the diet is equally important to maintain normal body weight. Studies focus on dietary fats and carbohydrates too as a factor for weight control.
Carbohydrate Quality Using Glycemic Index
Some of us have heard the term glycemic index while for others it might be something new. It was Jenkins et al. (1981) who used the term ‘glycemic index’ first to define carbohydrate quality. What is this glycemic index (GI)? It is nothing but the ability of the food to increase blood glucose 2 hours after eating that kind of food. According to Jenkins GI refers to the area under the blood glucose curve measured two hours after consuming 50g of carbohydrates with respect to the results obtained by consuming 50g of glucose or white bread. The term glycemic load (GL) was introduced in 1997 to quantify the overall glycemic effect of food with respect its specific carbohydrate content in typically consumed quantities. GL is calculated by multiplying amount of GI with carbohydrate amount in grams. High GI and GI diets are rapidly digested, absorbed and transformed into glucose which pave way for higher chances of glucose fluctuations, early signs of hunger and increased calorie consumption. Meanwhile, a low GI and GL diet takes time for digestion, releases glucose and insulin slower into the bloodstream and increases satiety levels decreasing calorie consumption. Maybe some of you now remember our physician’s clinic or hospital that notifies patients on the list of low GI and high GI foods that need to be consumed and avoided. But studies on the relationship between these indices with obesity rates in individuals come up with controversial results-either supporting, rejecting or showing no changes between the indexes and obesity rates.
A meta-analysis published in 2003 shows that low glucose index (LGI) are advantageous for glycosylated hemoglobin (HbA1c) in type 1 and type 2 diabetics compared to high glucose index (HGI) diets. We do have studies showing that consumption of high GI/GL diets increased the risk of type 2 diabetes. But most of these studies focus primarily on the adult population and the study below shows the effect of LGI and LGL on anthropometric parameters, blood lipid profiles and indicators of glucose metabolism in kids and teens below 18 years of age.
The systemic review was performed using the electronic databases MEDLINE and EMBASE with search terms such as ‘glycemic index’ and ‘glycemic load’. Apart from keywords other inclusion criteria were that they must be randomized control trials (RCT), age of participant <18 years of age, they must be humans and markers such as BMI, height, weight, waist circumference, hip circumference, waist-to-hip ration, systolic blood pressure (SBP), diastolic blood pressure (DBP) and fasting serum insulin (FI) must exist in the studies.
The search came up with a total of nine studies consisting of 1359 articles and 1065 participants that met the study criteria and was now eligible for meta-analysis. All the nine studies were randomized control trials (RCTs) which had a duration between 10 and 96 weeks. Results showed that:
Effect of Cohort Studies on Kids with Obesity
A study split participants into two teams-one team received a diet low-GI diet and the other a reduced-fat diet (emphasis was placed on limiting intake of high-fat, high-sugar and energy-dense foods while increasing consumption of grain products, vegetables and fruits). Though 190 participants were initially included only 107 remained as the others were not regular for follow-up. All the participants received medical evaluation, dietary counselling and lifestyle counselling in the presence of at least 1 parent. Each of them was called for follow-ups every month for the first 4 months and thereon, as and when needed.
In the reduced-fat intake group energy restrictions of approximately 1042 kJ to 2084 kJ per day was imposed compared to normal energy intakes. Macronutrient intake goals were set at 55-60% carbohydrates, 15-20% protein and 25-30% fats. The other diet was designed to provide the lowest GI possible but satisfying all nutrient requirements for kids. Here, there was more importance given to food selection and not energy restriction. This diet varied from regular diets mainly in the macronutrient ration where participants were asked to combine low-GI carbohydrate, protein and fat at every meal and snack. Macronutrient intake goals here were 45-50% carbohydrates, 20-25% proteins and 30-35% fats. Results showed that for each BMI tertile, the low-GI group showed a larger decrease in BMI compared to the reduced-fat group. Also, a larger percentage of patients in the low-GI group experienced a decrease in BMI compared to the reduced-fat group. Kids who were fed with reduced-fat diet showed no change in adjusted BMI whereas children fed with low-GI diet showed a BMI decrease of 1.15. A low-GI diet might promote weight loss by lowering insulin levels.
Effect of GI & GL on Brazilian Children
A study in Brazil conducted to observe the effect of glycaemic index and glycaemic load on hunger and high-energy intake and the risk of overweight/obesity and high adiposity in kids involved 5-year-old children whose adiposity, weight and nutrient index was assessed. GI of every food consumed by the kids was noted down and the kids were segregated into one of the 4 groups-under weight (7), normal weight (185), overweight (38) and obese (2). Overweight/obesity prevalence was 16.2% in the case of boys and 18.9% in case of girls. Meat, egg and margarine contain no carbs and do not contribute towards GI calculations. Only 87.7% of the foods in the food-frequency quantitative questionnaire (FFQQ) contributed to glycemic diet profile and the rest were categorized in the following frequencies: cereals and beans in 3-4*/week, milk/dairy products and sugar-added drinks in 2-3*/week, bakery products/biscuits, vegetables, fruits and sweets in 1-2*/week.
Results showed that kids from families with higher per capita income and moms with higher education levels had better glycemic profiles. Overweight group had a higher median carbohydrate intake than the normal weight group. It was generally seen that kids consumed significantly higher carbohydrate levels. They consumed more of cereals and beans followed by sugary drinks which are high in simple carbs thus contributing to an increased dietary GI. Fruits and vegetables that are low in GI and containing high fiber was consumed in lower proportions comparatively. Also, the cereals consumed were all refined ones. The study showed that the overweight group had higher GI and GL levels compared to the normal weight group.
Effects of Low Glycaemic Index/Low Glycaemic Load vs. High Glycaemic Index/High Glycaemic Load Diets on Overweight/Obesity & Associated Risk Factors in Children & Adolescents: https://nutritionj.biomedcentral.com/articles/10.1186/s12937-015-0077-1
A Low Glycaemic Index Diet in the Treatment of Paediatric Obesity: https://jamanetwork.com/journals/jamapediatrics/fullarticle/350858
Influence of Glycaemic Index & Glycaemic Load of the Diet on the Risk of Overweight & Adiposity in Childhood: https://www.sciencedirect.com/science/article/pii/S2359348216000129
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