foreach (var mealsViewModel in mealsListCollection)
            {
                foreach (var VARIABLE in mealsViewModel.Items)
                {
                    foreach (var d in VARIABLE.ArticlesAvailable)
                    {
                        d.ArticleQty = 0;

                    }

                }
            }

mealsListCollection.ForEach(u =>
                u.Items.Select(o => o.ArticlesAvailable.Select(c =>
                {
                    c.ArticleQty = 0;
                    return c;
                })));