I have been getting the same results for the search request from this link "https://spoonacular-recipe-food-nutrition-v1.p.mashape.com/recipes/search"
irrespective of the query i initialise in the header.

I’m currently on a free subscription plan

My current subscription plan

CUSTOM-POC
Classification : 5000/day
requests : 500/day
tiny requests : disabled

The following output is for the query = “Pizza”

[“X-Mashape-Key”: “my key”, “query”: “Pizza”]

{
“number” : 10,
“processingTimeMs” : 5,
“results” : [
{
“id” : 592479,
“title” : “Kale and Quinoa Salad with Black Beans”,
“readyInMinutes” : 50,
“image” : “Kale-and-Quinoa-Salad-with-Black-Beans-592479.jpg”,
“imageUrls” : [
“Kale-and-Quinoa-Salad-with-Black-Beans-592479.jpg”
]
},
{
“id” : 495111,
“title” : “Citrus Sesame Kale”,
“readyInMinutes” : 15,
“image” : “Citrus-Sesame-Kale-495111.jpg”,
“imageUrls” : [
“Citrus-Sesame-Kale-495111.jpg”
]
},
{
“id” : 540331,
“title” : “Strawberry Cinnamon Rolls”,
“readyInMinutes” : 50,
“image” : “Strawberry-Cinnamon-Rolls-540331.png”,
“imageUrls” : [
“Strawberry-Cinnamon-Rolls-540331.png”
]
},
{
“id” : 689502,
“title” : “Melt In Your Mouth Kale Salad”,
“readyInMinutes” : 10,
“image” : “Melt-In-Your-Mouth-Kale-Salad-689502.jpg”,
“imageUrls” : [
“Melt-In-Your-Mouth-Kale-Salad-689502.jpg”
]
},
{
“id” : 578102,
“title” : “Avocado chickpea salad (and a giveaway!)”,
“readyInMinutes” : 5,
“image” : “Avocado-chickpea-salad-(and-a-giveaway)-578102.jpg”,
“imageUrls” : [
“Avocado-chickpea-salad-(and-a-giveaway)-578102.jpg”
]
},
{
“id” : 483531,
“title” : “Black Bean and Barley Salad”,
“readyInMinutes” : 50,
“image” : “Black-Bean-and-Barley-Salad-483531.jpg”,
“imageUrls” : [
“Black-Bean-and-Barley-Salad-483531.jpg”
]
},
{
“id” : 695486,
“title” : “Green Smoothie”,
“readyInMinutes” : 10,
“image” : “green-smoothie-695486.jpg”,
“imageUrls” : [
“green-smoothie-695486.jpg”
]
},
{
“id” : 584495,
“title” : “Chopped Kale Salad with Pomegranate & Avocado”,
“readyInMinutes” : 15,
“image” : “Chopped-Kale-Salad-with-Pomegranate—Avocado-584495.jpg”,
“imageUrls” : [
“Chopped-Kale-Salad-with-Pomegranate—Avocado-584495.jpg”
]
},
{
“id” : 613079,
“title” : “Smashed White Bean and Avocado Sandwich”,
“readyInMinutes” : 10,
“image” : “Smashed-White-Bean-and-Avocado-Sandwich-613079.jpg”,
“imageUrls” : [
“Smashed-White-Bean-and-Avocado-Sandwich-613079.jpg”
]
},
{
“id” : 591746,
“title” : “Everything” White Bean Dip”,
“readyInMinutes” : 15,
“image” : “Everything-White-Bean-Dip-591746.jpg”,
“imageUrls” : [
“Everything-White-Bean-Dip-591746.jpg”
]
}
],
“baseUri” : “https://spoonacular.com/recipeImages/”,
“totalResults” : 10,
“isStale” : false,
“expires” : 1471024496121,
“offset” : 0
}

The following output is for the query = “Chicken”

[“X-Mashape-Key”: “my key”, “query”: “Chicken”]

{
“number” : 10,
“processingTimeMs” : 5,
“results” : [
{
“id” : 592479,
“title” : “Kale and Quinoa Salad with Black Beans”,
“readyInMinutes” : 50,
“image” : “Kale-and-Quinoa-Salad-with-Black-Beans-592479.jpg”,
“imageUrls” : [
“Kale-and-Quinoa-Salad-with-Black-Beans-592479.jpg”
]
},
{
“id” : 495111,
“title” : “Citrus Sesame Kale”,
“readyInMinutes” : 15,
“image” : “Citrus-Sesame-Kale-495111.jpg”,
“imageUrls” : [
“Citrus-Sesame-Kale-495111.jpg”
]
},
{
“id” : 540331,
“title” : “Strawberry Cinnamon Rolls”,
“readyInMinutes” : 50,
“image” : “Strawberry-Cinnamon-Rolls-540331.png”,
“imageUrls” : [
“Strawberry-Cinnamon-Rolls-540331.png”
]
},
{
“id” : 689502,
“title” : “Melt In Your Mouth Kale Salad”,
“readyInMinutes” : 10,
“image” : “Melt-In-Your-Mouth-Kale-Salad-689502.jpg”,
“imageUrls” : [
“Melt-In-Your-Mouth-Kale-Salad-689502.jpg”
]
},
{
“id” : 578102,
“title” : “Avocado chickpea salad (and a giveaway!)”,
“readyInMinutes” : 5,
“image” : “Avocado-chickpea-salad-(and-a-giveaway)-578102.jpg”,
“imageUrls” : [
“Avocado-chickpea-salad-(and-a-giveaway)-578102.jpg”
]
},
{
“id” : 483531,
“title” : “Black Bean and Barley Salad”,
“readyInMinutes” : 50,
“image” : “Black-Bean-and-Barley-Salad-483531.jpg”,
“imageUrls” : [
“Black-Bean-and-Barley-Salad-483531.jpg”
]
},
{
“id” : 695486,
“title” : “Green Smoothie”,
“readyInMinutes” : 10,
“image” : “green-smoothie-695486.jpg”,
“imageUrls” : [
“green-smoothie-695486.jpg”
]
},
{
“id” : 584495,
“title” : “Chopped Kale Salad with Pomegranate & Avocado”,
“readyInMinutes” : 15,
“image” : “Chopped-Kale-Salad-with-Pomegranate—Avocado-584495.jpg”,
“imageUrls” : [
“Chopped-Kale-Salad-with-Pomegranate—Avocado-584495.jpg”
]
},
{
“id” : 613079,
“title” : “Smashed White Bean and Avocado Sandwich”,
“readyInMinutes” : 10,
“image” : “Smashed-White-Bean-and-Avocado-Sandwich-613079.jpg”,
“imageUrls” : [
“Smashed-White-Bean-and-Avocado-Sandwich-613079.jpg”
]
},
{
“id” : 591746,
“title” : “Everything” White Bean Dip”,
“readyInMinutes” : 15,
“image” : “Everything-White-Bean-Dip-591746.jpg”,
“imageUrls” : [
“Everything-White-Bean-Dip-591746.jpg”
]
}
],
“baseUri” : “https://spoonacular.com/recipeImages/”,
“totalResults” : 10,
“isStale” : false,
“expires” : 1471024496121,
“offset” : 0
}

As you can see both my search requests are same.

Also my current subscription plan displays as “older version”.