Flank fat, often called “love handles,” frequently resists reduction even after consistent weight loss efforts. This resistance is not due to a lack of effort, but rather biological and physiological factors specific to the fat cells in this area. These deposits, located on the flanks and lower abdomen, are a type of subcutaneous fat that behaves differently from fat stored elsewhere in the body. Understanding the specific mechanisms that govern fat storage and release in this region explains why this fat is notoriously stubborn.
Why Fat Accumulates in the Flanks
The location where the body stores fat is determined by a combination of genetic factors and circulating hormone levels. Genetic factors primarily dictate an individual’s fat distribution pattern, creating a predisposition for storage in certain areas like the hips, thighs, or the abdominal region. This inherited pattern explains why some people gain weight primarily around the middle, while others gain it more easily in the lower body.
Hormonal signaling, particularly cortisol and sex hormones, is also a powerful determinant. Cortisol, often called the stress hormone, encourages fat deposition, especially in the abdominal area, which includes the flanks. Chronic stress can lead to sustained high cortisol levels, creating an environment that favors this type of central fat accumulation.
Sex hormones also significantly shape fat storage patterns. Premenopausal women typically store more subcutaneous fat in the lower body, often resulting in a “pear” shape. Men, and post-menopausal women due to decreased estrogen, tend to accumulate more fat in the abdominal and flank areas, contributing to an “apple” shape. A decrease in testosterone levels in men, for example, is associated with increased abdominal fat accumulation.
The Physiology of Stubborn Fat Loss
The primary reason flank fat is often the last to go lies in the biology of the fat cells themselves, specifically the ratio of two types of receptors on their surface: alpha-2 and beta adrenergic receptors. Fat mobilization (lipolysis) is the process of breaking down stored fat and releasing it into the bloodstream to be used as energy. This process is regulated by hormones like adrenaline and noradrenaline binding to these receptors.
Beta receptors are considered “pro-lipolytic”; their activation signals the fat cell to increase fat breakdown and release. Conversely, alpha-2 receptors are “anti-lipolytic,” meaning their activation inhibits or slows the fat-releasing process, essentially telling the fat cell to hold onto its stores.
Stubborn deposits like the flanks and lower abdomen have a disproportionately high density of inhibitory alpha-2 receptors compared to beta receptors. This adverse ratio means that even when the body is in a fat-burning state, the fat cells in the flanks receive a stronger “don’t release” signal. Consequently, fat is mobilized more readily from areas with a higher concentration of beta receptors before the stubborn areas are significantly affected.
Reduced Blood Flow
Reduced blood flow to these peripheral fat depots is another contributing factor to this stubbornness. Poor circulation means that fat-mobilizing hormones, even those stimulated by exercise, have a harder time reaching the fat cells in the flanks. Furthermore, even if the fat is successfully mobilized from the cells, the diminished blood flow makes it more difficult for the released fatty acids to be transported away to be burned as fuel elsewhere in the body. This physiological reality confirms why localized exercise, or “spot reduction,” is ineffective; working the underlying muscle cannot force specific fat cells to release their contents.
Systemic Approaches to Reduce Body Fat
Since fat loss is a systemic process, reducing flank fat requires a comprehensive strategy focused on lowering overall body fat percentage until the stubborn areas are finally targeted. The single most important factor for overall fat reduction is achieving a sustained calorie deficit, where the body consistently burns more energy than it consumes. This deficit forces the body to tap into stored energy, which includes fat reserves across the entire body.
A reasonable and sustainable deficit, often around 500 calories per day, can lead to a healthy weight loss rate of about one pound per week. However, the body will draw from the easiest-to-access fat stores first, meaning areas with fewer alpha-2 receptors will shrink before the flanks do. Patience and consistency are necessary, as the body must exhaust the more compliant fat before it moves on to the most resistant deposits.
Integrating a combination of resistance training and cardiovascular exercise is highly beneficial. Resistance training helps preserve and build muscle mass, which is important because muscle tissue is metabolically active and helps increase the resting metabolic rate. Preserving muscle ensures that the weight lost is primarily fat mass, rather than a mix of fat and muscle.
Cardiovascular exercise, particularly when performed at moderate to vigorous intensity, contributes significantly to energy expenditure, helping to widen the necessary calorie deficit. Regular exercise can also help improve systemic circulation, potentially benefiting the blood flow to those hard-to-reach fat deposits. Ultimately, reducing stubborn flank fat is a long-term commitment that relies on consistently maintaining a body-wide energy deficit until the body is forced to mobilize its most protected fat reserves.