By mentioning the opposite of something, its goodness is manifested. When Allah (swt), speaks about the hypocrites, He says:

(الْمُنَافِقُونَ وَالْمُنَافِقَاتُ بَعْضُهُم مِّن بَعْضٍ ۚ) (The hypocrite men and the hypocrite women are of one another). While, when He (swt) speaks about the believers, He says they are:

 (..بَعْضُهُمْ أَوْلِيَاءُ بَعْضٍ ۚ…)(allies of one another): What is the difference? Hypocrisy embraces all the evils – ugliness, lying, backbiting, gossip – all these together. As for the good person, it is different. A person may have good qualities in one aspect and bad characteristics in another. Therefore, he needs allies, who understand his weaknesses and help him overcome them and advise him. For example, there is a person who is good in many aspects but usually he lies. This kind of person needs a righteous one who advises and has an impact on him to get him back to straight path. This is in reference to Allah (swt) saying:

  وَالْعَصْرِ (1) إِنَّ الْإِنسَانَ لَفِي خُسْرٍ (2) إِلَّا الَّذِينَ آمَنُوا وَعَمِلُوا الصَّالِحَاتِ وَتَوَاصَوْا بِالْحَقِّ وَتَوَاصَوْا بِالصَّبْرِ 

(By time. Indeed, mankind is in loss. Except for those who have faith and do righteous deeds and are advising one another to truth and advising one another to patience) (Al-Asr)

…يَأْمُرُونَ بِالْمَعْرُوفِ…)) (They enjoin what is right,): Believers enjoin what is commonly recognized as good and what leads to goodness for others. When you do not steal from the wealth of others, do not lie to others, do not backbite others, speak only kind words, and enjoin what is right, accordingly who benefits from your good character? Certainly, others will. Hence, the goodness means enjoining of good and forbidding of evil. In Islam, goodness is based on the well-known and agreed-upon values of society that are regulated by ethical principles brought by divine messages.

…وَيُقِيمُونَ الصَّلَاةَ وَيُؤْتُونَ الزَّكَاةَ…  (and establish prayer and give zakah,): Enjoining what is right is proceeded with establishing prayer and giving almsgiving because the prayer represents a continuous expression of loyalty to Allah (swt), and it is the cornerstone of faith. Along with prayer, there must be a form of affirmation, which is spending money in the way of Allah (swt). It means that a person should support his fellow human not only morally but also, if needed, financially.

…وَيُطِيعُونَ اللَّهَ وَرَسُولَهُ ۚ… (and obey Allah and His Messenger,): Because Islam is not represented though just the pillars. The prayer, fasting, almsgiving, pilgrimage, and the two testimonies of faith are the pillars of Islam, as the Prophet Muhammad (saws) said:

“ Islam has been built on five [pillars]: testifying that there is no deity worthy of worship except Allah and that Muhammad is the Messenger of Allah, establishing the salah (prayer), paying the zakat (obligatory charity), making the hajj (pilgrimage) to the House, and fasting in Ramadhan.”[1]

He (saws) said “Islam has been built on five [pillars]”: and did not say, ‘The 5 pillars are what Islam is’. This is because Islam encompasses all the commands of Allah (swt), and every command that begins with: (Oh you who have believed): shows a part of Islam. When the Quran says:

  يَا أَيُّهَا الَّذِينَ آمَنُوا كُتِبَ عَلَيْكُمُ الصِّيَامُ كَمَا كُتِبَ عَلَى الَّذِينَ مِن قَبْلِكُمْ لَعَلَّكُمْ تَتَّقُونَ 

(Oh you who have believed, fasting has been prescribed upon you as it was prescribed upon those before you that you may become righteous) (Al-Baqara: 183)

So, fasting is part of Islam. When Allah (swt) says:

 يَا أَيُّهَا الَّذِينَ آمَنُوا كُلُوا مِن طَيِّبَاتِ مَا رَزَقْنَاكُمْ وَاشْكُرُوا لِلَّهِ إِن كُنتُمْ إِيَّاهُ تَعْبُدُونَ 

(Oh you who have believed, eat from the good things which We have provided for you and be grateful to Allah if it is [indeed] Him that you worship) (Al-Baqara: 172)

So, eating healthy food is part of Islam.

As well as other commands such as:

   يَا أَيُّهَا الَّذِينَ آمَنُوا أَنفِقُوا مِمَّا رَزَقْنَاكُم  

(Oh you who have believed, spend from that which We have provided for you) (Al-Baqara: 254)

  يَا أَيُّهَا الَّذِينَ آمَنُوا لَا يَحِلُّ لَكُمْ أَن تَرِثُوا النِّسَاءَ كَرْهًا ۖ وَلَا تَعْضُلُوهُنَّ لِتَذْهَبُوا بِبَعْضِ مَا آتَيْتُمُوهُنَّ إِلَّا أَن يَأْتِينَ بِفَاحِشَةٍ مُّبَيِّنَةٍ ۚ وَعَاشِرُوهُنَّ بِالْمَعْرُوفِ ۚ فَإِن كَرِهْتُمُوهُنَّ فَعَسَىٰ أَن تَكْرَهُوا شَيْئًا وَيَجْعَلَ اللَّهُ فِيهِ خَيْرًا كَثِيرًا 

(Oh you who have believed, it is not lawful for you to inherit women by compulsion. And do not make difficulties for them in order to take [back] part of what you gave them unless they commit a clear immorality. And live with them in kindness. For if you dislike them – perhaps you dislike a thing and Allah makes therein much good) (An-Nisa’: 19)

Here, being kind to women is also part of Islam.

He says, also:

  يَا أَيُّهَا الَّذِينَ آمَنُوا لَا تَأْكُلُوا أَمْوَالَكُم بَيْنَكُم بِالْبَاطِلِ إِلَّا أَن تَكُونَ تِجَارَةً عَن تَرَاضٍ مِّنكُمْ ۚ وَلَا تَقْتُلُوا أَنفُسَكُمْ ۚ إِنَّ اللَّهَ كَانَ بِكُمْ رَحِيمًا  

(Oh you who have believed, do not consume one another’s wealth unjustly but only [in lawful] business by mutual consent. And do not kill yourselves [or one another]. Indeed, Allah is ever Merciful to you) (An-Nisa’: 29)

Thus, avoiding the unlawful is also part of Islam.

This is Islam. It is obedience in all that He (swt) has commanded, and refraining from all that He (swt) has prohibited and discouraged.

…أُولَٰئِكَ سَيَرْحَمُهُمُ اللَّهُ ۗ…)) (Those – Allah will have mercy upon them.):  saying “will have mercy” in the future tense instead of the present form, serves a significant purpose of encouraging, as when Allah (swt) says:

  إِنَّ الَّذِينَ آمَنُوا وَعَمِلُوا الصَّالِحَاتِ سَيَجْعَلُ لَهُمُ الرَّحْمَٰنُ وُدًّا 

(Indeed, those who have believed and done righteous deeds – the Most Merciful will appoint for them affection.) (Maryam: 96)

“will” indicates the future. so you are always anticipating the mercy of Allah (swt).

…إِنَّ اللَّهَ عَزِيزٌ حَكِيمٌ  (Indeed, Allah is Exalted in Might and Wise.): Allah is Mighty and Unconquerable. And He is Wise in placing things in their correct order.

[1] Sohih Bukhari: The Book of Faith, Chapter: Faith and the saying of the Prophet (saw): (Islam is built upon five..), Hadith no. 8