Unhealthiest Fast Food Milkshakes, Ranked

Ordering a regular milkshake with your fast food meal feels harmless enough — until you realize it might be the most over-the-top thing in the bag.

PlushCare analyzed vanilla shakes from 14 major fast food chains, breaking each one down by energy, fat, sugar, and sodium to calculate a final unhealthiness score. We also looked at the full nutritional breakdown for each shake to give you a clearer picture of what you’re actually drinking sugar and fat were the usual suspects, but a few shakes also came loaded with way more salt than you’d expect from something sweet.

Here’s how they all ranked, from the least to the most unhealthy.

14. McDonald’s: Vanilla Shake

Unhealthiness Score: 26

1. Energy: 6
2. Fat: 8
3. Sugar: 11
4. Sodium: 2

Mickey D serves one of the lightest shakes on the “feel guilty” scale, but don’t get too smug. A regular shake here still comes with around 62 grams of sugar, which is way more than what your dentist thinks you deserve in a day.

13. Smashburger: Vanilla Shake

Unhealthiness Score: 27

1. Energy: 8
2. Fat: 2
3. Sugar: 12
4. Sodium: 5

Smashburger flies under the radar but don’t be fooled — it’s a caloric sneak attack. At 760 calories and 61 grams of sugar, it’s one of the fattiest options on the list (46 grams of fat).

12. Arby’s: Vanilla Shake

Unhealthiness Score: 33

1. Energy: 5
2. Fat: 11
3. Sugar: 14
4. Sodium: 3

Arby’s shake comes with 64 grams of sugar, accompanied by a whipped topping that may look innocent but isn’t. We wouldn’t be mad if it came with a straw and a warning label.

11. Burger King: Vanilla Shake

Unhealthiness Score: 36

1. Energy: 6
2. Fat: 9
3. Sugar: 17
4. Sodium: 4

501 calories, 26 grams of fat, the King serves a decent shake until you remember it’s supposed to be the small size. Good luck walking upright if you pair this with a Whopper.

10. Whataburger: Medium Vanilla Shake

Unhealthiness Score: 39

1. Energy: 6
2. Fat: 9
3. Sugar: 19
4. Sodium: 5

Whataburger’s Medium Vanilla Shake contains 86 grams of sugar—a dessert-level amount without factoring in the 510 calories.

9. Steak ‘n Shake: Regular Vanilla Shake

Unhealthiness Score: 41

1. Energy: 7
2. Fat: 12
3. Sugar: 20
4. Sodium: 2

This hand-dipped shake has that dense, custard-like texture people swear by—but nutritionally, it’s a red flag. With 92 grams of sugar, you’re basically downing 23 teaspoons in one go. Enough to give a sugar rush to a rock.

8. Jack in the Box: Vanilla with Whipped Topping

Unhealthiness Score: 42

1. Energy: 7
2. Fat: 17
3. Sugar: 15
4. Sodium: 3

The whipped cream and cherry make it look friendly, but it’s one of the fattiest on the list. Jack’s shakes are made from a base that leans more artificial, so you’re getting flavor over quality ingredients.

7. In-N-Out: Vanilla Shake

Unhealthiness Score: 43

1. Energy: 7
2. Fat:20
3. Sugar: 12
4. Sodium: 4

In-N-Out uses real ice cream, which you can tell from the thicker texture. It’s simpler and slightly more balanced than most shakes here, but it still comes with a nutritional baggage of 590 calories, 55 grams of sugar, and 31 grams of fat.

6. Dairy Queen: Vanilla Shake

Unhealthiness Score: 44

1. Energy: 8
2. Fat:16
3. Sugar:18
4. Sodium: 2

DQ uses soft serve as the base, so it’s smooth and sweet but also aerated, meaning it’s easier to drink fast, which is not the best idea, given it has 65 grams of sugar.

5. A&W: Regular Vanilla Shake

Unhealthiness Score: 47

1. Energy: 8
2. Fat: 14
3. Sugar: 20
4. Sodium: 5

This shake has 900 calories and 70 grams of sugar — the highest sugar so far on the list, and half a day’s worth of calories before you’ve even had lunch.

4. Carl’s Jr.: Vanilla Shake

Unhealthiness Score: 50

1. Energy: 9
2. Fat: 24
3. Sugar: 15
4. Sodium: 2

The hand-scooped shake tastes legit because it is — but it’s also one of the heaviest here, with 740 calories, 70 grams of sugar, and 36 grams of fat.

3. Five Guys: Base Vanilla Shake

Unhealthiness Score: 51

1. Energy: 8
2. Fat: 21
3. Sugar: 18
4. Sodium: 4

Before adding any toppings, the base shake is already intense, with 670 calories and 84 grams of sugar. Add-ins like peanut butter or Oreos push it well past the 1,000 mark.

2. Sonic: Medium Vanilla Shake

Unhealthiness Score: 55

1. Energy: 8
2. Fat: 20
3. Sugar: 20
4. Sodium: 7

This medium shake comes in at 710 calories and 92 grams of sugar, with a surprising 630 milligrams of sodium. It’s a full-blown meal with a straw.

1. Fatburger: Vanilla Shake

Unhealthiness Score: 63

1. Energy: 11
2. Fat: 30
3. Sugar: 19
4. Sodium: 3

Well, it’s not called Lightburger. Fatburger’s Vanilla Shake takes the crown as the worst for your health with 890 calories, 86 grams of sugar, and 44 grams of fat. It’s an absolute monster of a shake and fully owns it.