Does Fat in our diet really result in weight gain?
The increase in fat intake in the modern diet and reduced physical activity are the two major factors in the development of obesity in industrialised countries. I am currently working with Elate Wellbeing Gurugam as a nutritionist and weight loss consultant, and I have been a diet expert for weight loss for almost a decade. But I still see some people finding great difficulty in losing the extra weight.
The notion that you’re doing a lot of workouts so you can eat almost anything is completely wrong. Your physical activity accounts for only 30% of your weight loss efforts, the rest is all your diet plan. Yoga Experts at Elate Wellbeing have also vouched for the fact that there are a lot of loopholes in the kind of lifestyle most people follow in metro cities. What you are eating is very much connected to what you are. And it is not just the weight anymore, your body needs to maintain a balance in between body fat % and total lean mass (weight minus your body fat content) or your total muscle mass. If you are losing fat from the body, gaining muscle in the healthy thing to do. Due to this reason sometimes the numbers on the scale might not always go down, but that’s okay!
Fat is the most energy-dense nutrient in our daily diet, producing 9 calories per gram, which is more than twice the calories derived from other macronutrients like carbohydrates and proteins. At the same time, fats are more efficiently metabolised in the body and stored as body fat than carbohydrates are. Although very fatty foods provide a large number of calories, in parallel with an intense feeling of enjoyment and pleasure, they do not produce a strong feeling of satiety.
For this reason, they are usually overconsumed, which encourages the passive overconsumption of calories and the development of obesity, by effecting body’s total energy balance. Overconsumption and the extra amount of dietary fat intake can lead to its storage in fat tissue (in percentage terms sometimes as high as 96%). Thus, an initial recommendation to lower dietary fat intake to initiate significant weight loss is reasonable and supported by scientific literature and research.
One of the main mechanisms through which dietary fats can contribute to the development of obesity is the regulation of leptin levels. Experiments have shown that increased fat intake results in central leptin resistance, whereas the restriction of dietary fat intake can improve the leptin signalling, which results in spontaneous reduction appetite and body weight.
Regulation of Energy Expenditure, Food Intake and Body Weight by Leptin:
Leptin is an important component in the long-term regulation of body weight. Recent studies with obese and non-obese humans demonstrated a strong positive correlation of serum leptin concentrations with the percentage of body fat. It appears that as adipocytes increase in size due to the accumulation of triglyceride, they synthesize more and more leptin. Leptin's effects on body weight are mediated through effects on hypothalamic centres that control feeding behaviour and hunger, body temperature and energy expenditure.
Leptin in Obesity
Leptin is a neurotransmitter expressed in the brain. This neurotransmitter signals to the brain mainly in the hypothalamus that when a person stops to eat for maintaining his Body Mass Index. It has been observed that there is a considerable genetic impact when it comes to successful leptin hormone receptors. Some people have a polymorphism in the leptin gene. Mutations in this gene prevent to manufacture the functional leptin protein. Due to less leptin expression, we become morbidly obese. Another gene type has a mutation or polymorphism in the gene encoding for the Leptin Receptor. In this case, signal of the leptin is not received by the brain or the hypothalamus. So due to signal disruption or mutations in the leptin receptor, humans tend to become obese.
Obesity is an increasing problem in affluent societies. By definition, the development of obesity is characterized by a mismatch between energy intake and energy expenditure. Apart from genetic factors that have been suggested to lead to obesity, the rapid development of obesity in Western societies has mostly been attributed to a reduction in levels of physical activity and an increase in the consumption of high-fat, energy-dense (fast) foods.
From the data available in the literature, it has been shown that a high dietary fat intake contributes to the current obesity epidemic. Long-term intervention trials using a reduced-fat diet consistently show a small but significant reduction in body weight. However, dietary fat is not the sole food component that can explain the huge increase in obesity prevalence.
The most important mechanism through which dietary fat might exert its effect on energy balance is via its effect on energy density. Future research should be focused on studying the effect of low-energy-dense diets in the development of obesity and campaigns promoting healthy diets should take the energy density into account in their diet recommendations. The food industry could play an important role in the battle against obesity by producing and promoting healthy low-fat, low-energy-dense food products.