The Propensity of Mankind to Pursue Diet as a Means to Reduce Abdominal Obesity

Eliminating Belly Fat is not an Easy Task! It Requires Determination & Perseverance

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.

Abdominal Fat
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.
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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.
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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.
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Results
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.

References
Therapeutic Treatment for Abdominal Obesity in Adults: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6121087/
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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
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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