Best meditation techniques (mindfulness,vipassana,yoga,zazen,TM,etc) to beat behavioral addictions (food,sex,porn,gambling,internet,videogames,etc)?

See also e.g. here for some "non-meditative practices or measures".

Also, "food" is difficult and a separate category: because you can't just cut it out completely. Instead you should eat moderately, measuredly -- see e.g. Sariputto Sutta (SN 35.120) which mentions guarding the sense-doors, and which says,

And how, friend, is one moderate in eating? In this a monk takes his food properly considering,² not for sport, for intoxication, for adornment or beautification, but purely for the maintenance and nourishment of this body, for keeping it unharmed, as an aid to the practice of the holy life, thinking:

"I shall put an end to the old feeling,³ and not produce any new feeling.⁴ Thus I shall keep going, incur no fault, and live at ease."

That, friend, is how one is moderate in eating.

² With due attention (yoniso)
³ Of hunger.
⁴ Of greed.

The Buddhist path has four right efforts, namely:

1. Effort to prevent

2. Effort to abandon or cure

3. Effort to develop

4. Effort to maintain.

The question & some answers (such as the video of Yuttadhammo) are about efforts to abandon rather than effort to prevent.

Prevention is better than cure. Prevention uses reasoned thinking about the harm & danger of these addictions. The objects of addiction should be viewed is the same way as reasonable people view drugs like heroin. Pornography, for example, destroys the lives of women, for example:

Jenna Jameson (born Jenna Marie Massoli; April 9, 1974) is an American entrepreneur, webcam model and former p**nographic film actress, who has been called the world's most famous adult entertainment performer and "The Queen of Porn".

Jameson announced in August 2008 that she and Ortiz were expecting twins in April 2009.On March 16, 2009, Jameson gave birth to twin boys, Jesse Jameson and Journey Jette. Jameson and Ortiz split up in March 2013. Ortiz was granted full custody of the twins

As of 2014, Jameson has undergone extensive tattooing, almost completely covering both of her arms in sleeve tattoos. In 2013, self-proclaimed socialite and writer Britney Markham became Jameson's personal assistant after having met on Twitter. In a 2014 interview with LA Weekly, Markham claimed that Jameson would make requests for drugs. Markham posited that the pills of choice were Xanax, Ambien and Suboxone along with alcohol. At the same time, Markham denied that Jameson had been taking Oxycodone, in spite of previous rumors. Markham stated that she was assaulted and battered by Jameson following an incident in a hair salon in Los Angeles in 2013 when Jameson punched Markham in the stomach with a brass knuckles iPhone case. The blow was so severe, Markham claims she vomited blood and was hospitalized.

On August 5, 2016, Jameson announced that she and her Israeli boyfriend, Lior Bitton, were expecting their first child together. On April 6, 2017, they welcomed a daughter, Batel Lu.

On November 11, 2016, Jameson announced on her Twitter feed that she completed her conversion to Orthodox Judaism with a Haredi rabbinical court in Upstate New York. Having been raised Catholic, in June 2015, Jameson announced that she was converting to Judaism, in order to marry Bitton. In October, an Israel Channel 2 reality television series was announced, which would document Jameson's conversion.

Pornography is a charade, lie & deception, which is upheld by the false view or false idea that the women in p**nography are happy & having fun. If a person has right view & has compassion for women, they will not be tempted to view p**nography because they understand p**nography harms women (as well as men).

OP: For a layman who wants to overcome behavioral addictions, ... which meditation techniques are the most recommendable?

Please see this answer about a video talk by Yuttadhammo Bhikkhu on addiction to p**nography and addiction in general. That answer also states:

The other technique he proposes is to watch your mind for triggers and observe how lust arises in the mind and recognize it (basically insight meditation). You can find more info on this in his chapter entitled "Daily Life" of his booklet "How To Meditate".

I believe this technique can be applied to most, if not all, addictions.

OP: Additionally, given the fact that an average layman cannot afford going full-time monk, what would be a recommendable frequency (in terms of minutes/hours per day) to see palpable results in a reasonable time?

Please see this question for good answers.

OP: Is a single meditation technique enough to overcome behavioral addictions? Or would it better to practice multiple meditation techniques at the same time? Or maybe different meditation techniques for different situations?

One way suggested by Yuttadhammo Bhikkhu to overcome sexual addiction is to mentally take apart and analyze the parts of the body (the so-called contemplation on unattractiveness or asubha). You can find some info in this question and this question. But also see this answer - this type of contemplation should be replaced with the mindfulness of breathing if it triggers negative thoughts of suicide.

The other technique he proposes is to watch your mind for triggers and observe how lust arises in the mind and recognize it (basically insight meditation). You can find more info on this in his chapter entitled "Daily Life" of his booklet "How To Meditate".

So, here you have two techniques for sexual addition.

Regarding food addiction, you can try the insight method above, or the gradual food reduction method in this answer.

OP: Is meditation as a whole enough, or would one need to complement it with other non-meditative practices or measures?

The practice of the five precepts and virtue (sila) with heedfulness (appamada) is recommended. In addition, eating, sleeping, consuming entertainment and socializing should be done in moderation.

You can find this in the "Daily Life" chapter of Yuttadhammo Bhikkhu's booklet "How to Meditate":

Meditation is meant to cultivate clarity and understanding, free from addiction, aversion, and delusion, and therefore free from suffering. Since certain bodily and verbal acts are intrinsically tied to negative qualities of mind, they are considered ‘contraindicative’ to the meditation practice; they have an effect opposite to what is desired, cultivating defilement instead of purity. Meditators who insist on engaging in such behaviour will face great difficulty in their practice, developing habits that are detrimental to both meditation practice and personal well-being. To ensure the mind is perfectly clear and capable of understanding reality, certain behaviours must be taken out of one’s “diet”, so to speak.

First, there are five kinds of action from which one must refrain completely, as they are inherently unwholesome:

1. One must refrain from killing living beings. In order to cultivate one’s own well-being, one must be dedicated to well-being as a principle, refraining from killing any living being, even ants, mosquitoes and other living beings.

2. One must refrain from theft. In order to find peace of mind, we must grant it to others as well; stealing is a denial of this basic right to security. Further, if we wish to be free from addiction, we must be able to control our desires to the extent of respecting the possessions of others.

3. One must abstain from committing adultery or sexual misconduct. Romantic relationships that are emotionally or spiritually damaging to others, due to existing commitments of the parties involved, are a cause for stress and suffering and based on perversion of the mind.

4. One must refrain from telling lies. If one wishes to find truth, one must avoid falsehood; intentionally leading others away from the truth is harmful both to oneself and others and incompatible with the goals of meditation.

5. One must refrain from taking drugs or alcohol. Any substance that intoxicates the mind is obviously contraindicative to meditation practice, as it is the antithesis of a natural, clear state of being.

Complete abstention from these activities is necessary if one wishes for meditation practice to be successful, due to their inherently unwholesome nature and the invariably negative effect they have on the mind.

Further, there are certain activities that must be moderated or they will interfere with meditation practice. These are activities that are not necessarily unwholesome in and of themselves but will nonetheless inhibit clarity of mind and lessen the benefit of the meditation practice when undertaken in excess.

One such activity is eating; if one wishes to truly progress in the meditation practice, one must be careful not to eat too much or too little. If one is constantly obsessed with food, it can be a great hindrance to progress in meditation since not only does it cloud the mind, over-eating leads to drowsiness, both in the body and mind. One should eat to stay alive rather than stay alive simply to eat. During intensive meditation courses, meditators eat one main meal per day and suffer no negative physical consequences as a result; whereas the positive effects of such moderation are clarity of mind and freedom from obsession over food.

Another activity that interferes with meditation practice is entertainment – watching movies, listening to music, and so on. These occupations are not inherently unwholesome but can easily create states of addiction when undertaken in excess.

Addiction is a form of insobriety in a sense, since it involves chemical processes in the brain that inhibit clear thought and clarity of mind. Since the pleasure that comes from entertainment is momentary and unsatisfying while the addiction and obsession carry over into one’s life, a serious meditator should determine to make the best use of their short time in this life by cultivating peace and contentment, rather than wasting it on meaningless activities that don’t lead to long term happiness and peace. If one wishes to find true happiness, one must therefore moderate one’s engagement in entertainment. Socializing on the Internet and similar activities should be undertaken in moderation as well.

The third activity one must moderate is that of sleeping. Sleeping is an addiction that is often overlooked; most people don’t realize how attached they are to sleep as a means of escape from reality. Still others become insomniac, obsessed with the thought that they are not getting “enough” sleep, leading to increased stress levels and further difficulty in falling asleep.

Through the meditation practice, one will find that one needs less sleep than before since one’s mind will become calmer. Insomnia is not a problem for meditators since they are able to meditate even in the lying position and keep their minds free from stress. People who have difficulty falling asleep should train themselves to watch the stomach rise and fall, noting “rising”, “falling”, all night if necessary. Even if they are not able to fall asleep (which is unlikely, given the calm state of mind while meditating) they will find themselves as rested as if they had slept soundly through the night.

Finally, it is worth mentioning that to truly gain results in the meditation practice, a meditator should set aside at least a period of time to remain entirely celibate, not just avoiding immoral sexual activity, since all sexual activity is invariably intoxicating and will be a hindrance towards attainment of mental clarity and peace.