NutritionZ

{
    "minecraft:cooked_cod": { // The default datapacks provide 5 points for half saturation
        "carbohydrates": 0,
        "protein": 16,
        "fat": 3,
        "vitamins": 0,
        "minerals": 6
    }
}

{
    "minerals": {
        "replace": true,
        "positive": {
            "generic.armor_toughness": { // attribute
                "operation": "ADD_VALUE", // ADD_VALUE, ADD_MULTIPLIED_BASE , ADD_MULTIPLIED_TOTAL
                "value": 1.0 // gives +1 Armor Toughness per level -> e.g. +20 max level
            },
            "minecraft:haste": { // effect
                "duration": 319, // wouldn`t recommend to lower this on effects
                "amplifier": 0 // equals Haste I
            }
        },
        "negative": {
            "generic.armor_toughness": {
                "operation": "ADD_VALUE",
                "value": 1.0 // needs to be positive value -> will be negative automatically
            },
            "minecraft:mining_fatigue": {
                "duration": 319,
                "amplifier": 0
            }
        }
    }
}

{
    "maxNutrition": 100, // Max nutrition for one nutrient
    "negativeNutrition": 10, // 0 - 10 = negative effects / attributes (negative threshold)
    "positiveNutrition": 90, // 90 - 100 = positive effects / attributes (positive threshold)
}

Credits