Could someone possibly tell me why my sprite doesnt change please ?

Title says it sprite doesnt change everything else works eny ideas why ?

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
public class SpriteChanger : MonoBehaviour {
	public Sprite sprite1;
	public Sprite sprite2; 
	private SpriteRenderer spriteRenderer; 
	static public double coins = 0.00;
	static public int Potatos = 0;
	static public int Lemons = 0;
	static public int Apples = 0;
	static public float Hunger = 0;
	public Text CoinsText;
	public Text PotatoText;
	public Text LemonText;
	public Text AppleText;
	public Text Hungerprocent;
	void Start ()
	{
		

		spriteRenderer = GetComponent<SpriteRenderer>(); 
			spriteRenderer.sprite = sprite1; 
	}

	void Update ()
	{


		if (Hunger >= 70) { 
			ChangeTheDamnSprite ();
			coins = 0;
		}
		if (Hunger > 75) { 
			Hunger -= 50;
		}


		CoinsText.text = "" + coins ;
		PotatoText.text = "" + Potatos;
		LemonText.text = "" + Lemons;
		AppleText.text = "" + Apples;
		Hungerprocent.text = "Hunger = " + Hunger;

	}

	void ChangeTheDamnSprite ()
	{
		if (spriteRenderer.sprite == sprite1 ) {
			if (Hunger >= 70) { 
				spriteRenderer.sprite = sprite2;
			}
		}
		if (spriteRenderer.sprite == sprite2){
			if (Hunger < 70) {
				spriteRenderer.sprite = sprite1;
			}
		}

	}
}

Hunger starts at 0 so the block in if (Hunger >= 70) is never called.