Is spot reduction necessarily a myth?

Question

I have always known this to be a fact that spot reduction is a myth, but this article tends to claim otherwise.

Here is a point, I'd like to highlight from the article:

Theoretically, we have a good reason to believe spot reduction may occur. We know that spot lipolysis is real: you acutely burn more fat in fat regions near active muscles than in fat regions distant from active muscles. Concretely, when you are exercising your left leg, more fat is burned off from your left thigh than your right thigh. The local fat oxidation appears to be the result of the increased temperature and blood flow near the exercised tissue. This may increase the delivery of fat burning hormones like epinephrine and norepinephrine. Myokines released by the active muscle, like IL-6, may also increase fat oxidation rates in nearby fat tissue.

Answer 1

In my opinion, spot reduction is still a myth if you consider how spot reduction has been defined for years. The study as well as another article I found, are both pro-spot-reduction but I don't think it is in the same sense as what most people think.

When I think spot reduction, I think that if all I do is crunches then I'm going to burn fat in my mid-section only and not impact anything else. This definition is entirely untrue. It is impossible to promote fat loss in an isolated portion of the body.

If we change the definition of spot reduction to be an optimal diet with a core-focused high-intensity strength workout followed by high-intensity cardio to minimally increase the efficiency of fat burn in the mid-section then yes, I think it has some merit. You're burning fat across the whole body and possibly burning fat somewhat more efficiently at the targeted muscle site. Is this really spot reduction?

This study sums it up pretty nicely from my perspective:

And, so far as I’m concerned, that should be the death knell for the idea of spot reduction. Yes, there appears to be an effect whereby working a given muscle impacts local fat cell metabolism but the effect is completely and utterly irrelevant in quantitative terms. The amount of fat mobilized due to increased hormones or blood flow is simply insignificant to anything in the real world.

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As an aside, the article you linked has some red flags:

Spot reduction is also reported after application of certain pharmaceutical injections and ointments [1, 2], though you probably don’t want to put much stock in any of the commerically available ‘fat loss creams’.

This is entirely untrue. The studies have participants use pharmaceutical grade weight loss creams in addition to a reduced-calorie diet. Having this statement in there really makes me dislike the article entirely.

In 2013, a novel study design was used to test the possibility of spot reduction. This time the study participants did high repetition leg presses with one leg without training the other leg. The trained leg did not lose more fat than the untrained leg.

[...]

Concretely, when you are exercising your left leg, more fat is burned off from your left thigh than your right thigh.

They have this quote in the article (you mentioned it yourself) however they previously mentioned a study where this was incorrect (i.e. they contradict themselves). The study where there is no difference is cited, the secondary statement is not cited.

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I do agree with the following quote.

So if you’re a man that wants a slimmer midsection, heavy ab work may be counterproductive if the muscle growth thickens your obliques to a greater extent than you induce spot reduction of the abdominal fat mass.

For women, heavy triceps work to spot reduce the upper arm fat may be similarly counterproductive if no arm muscle growth is desirable.

This is probably the biggest point working against this redefinition of spot reduction.

Answer 2

I joined this community to explore this topic. Once I learned the term spot reduction, I did a search. Here's what I found [emphasis added]:

Accumulation of adipose tissue in specific body areas is related to many physiological and hormonal variables. Spot reduction (SR) is a training protocol aimed to stimulate lipolysis locally, even though this training protocol has not been extensively studied in recent years. Thus, the present study sought to investigate the effect of a circuit-training SR on subcutaneous adipose tissue in healthy adults. Methods: Fourteen volunteers were randomly assigned to spot reduction (SR) or to a traditional resistance training (RT) protocol. Body composition via bioimpedance analysis (BIA) and subcutaneous adipose tissue via skinfold and ultrasound were measured before and after eight weeks of training. Results: SR significantly reduced body mass (p < 0.05) and subcutaneous abdominal adipose tissue (p < 0.05). Conclusions: circuit-training SR may be an efficient strategy to reduce in a localized manner abdominal subcutaneous fat tissue depot.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8038840/

I have always intuitively believed that "hitting the place where the fat is" will effectively target the fat there. Medical professionals have never provided me with a decisive answer as to a scientific validation of this belief.